Isopropylphenidate
Studies and references cited across this article, graded by evidence strength.
Inconclusive means the cited source neither confirms nor refutes the claim — a lower-confidence badge, not an error.
Data points an editor reviewed and accepted for publication.
Value Provenance
Dosing
oraltrace
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Threshold | 2 mg | 2 mg | low |
| Low | 5–15 mg | 5–15 mg | low |
| Common | 15–25 mg | 15–25 mg | low |
| Strong | 25–45 mg | 25–45 mg | low |
| Heavy | 45+ mg | 45+ mg | low |
| Editorial | Existing DB values (community consensus from PsychonautWiki and user reports). No published human dose-response data. US patent specifies 10-100 mg/dose range, consistent with but broader than community ranges. No LD50 data exist — heavy threshold carries unquantified toxicity risk. | ||
ReasoningReasoningExisting DB values (community consensus from PsychonautWiki and user reports). No published human dose-response data. US patent specifies 10-100 mg/dose range, consistent with but broader than community ranges. No LD50 data exist — heavy threshold carries unquantified toxicity risk. Evidence basis: community_consensus_large | |||
insufflatedtrace
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Threshold | 2 mg | 2 mg | low |
| Low | 5–10 mg | 5–10 mg | low |
| Common | 10–20 mg | 10–20 mg | low |
| Strong | 20–35 mg | 20–35 mg | low |
| Heavy | 35+ mg | 35+ mg | low |
| Editorial | Existing DB values (community consensus). Insufflated ranges are lower than oral, consistent with bypassing first-pass metabolism and faster absorption. No published human PK or dose-response data. Compulsive redosing risk is elevated via this ROA. | ||
ReasoningReasoningExisting DB values (community consensus). Insufflated ranges are lower than oral, consistent with bypassing first-pass metabolism and faster absorption. No published human PK or dose-response data. Compulsive redosing risk is elevated via this ROA. Evidence basis: community_consensus_large | |||
Duration
oral
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Onsettrace | 10–30 minutes | 10–30 minutes | low |
| Editorial | Existing DB values (community consensus). Consistent with rodent data showing locomotor onset within ~10 minutes (Markowitz 2013). No human PK data. | ||
ReasoningReasoningExisting DB values (community consensus). Consistent with rodent data showing locomotor onset within ~10 minutes (Markowitz 2013). No human PK data. Evidence basis: community_consensus_large | |||
| Come uptrace | 20–40 minutes | 20–40 minutes | low |
| Editorial | Existing DB values (community consensus). No human PK data. | ||
ReasoningReasoningExisting DB values (community consensus). No human PK data. Evidence basis: community_consensus_large | |||
| Peaktrace | 1.5–2.5 hours | 1.5–2.5 hours | low |
| Editorial | Existing DB values (community consensus). Consistent with sustained activity >120 min in rats (Markowitz 2013). | ||
ReasoningReasoningExisting DB values (community consensus). Consistent with sustained activity >120 min in rats (Markowitz 2013). Evidence basis: community_consensus_large | |||
| Offsettrace | 1–2 hours | 1–2 hours | low |
| Editorial | Existing DB values (community consensus). No human PK data. | ||
ReasoningReasoningExisting DB values (community consensus). No human PK data. Evidence basis: community_consensus_large | |||
| Totaltrace | 3.5–6 hours | 3.5–6 hours | low |
| Editorial | Existing DB values (community consensus). Consistent with IPH's 10-fold CES1 resistance producing longer duration than MPH (2-4 hours). Article prose states 3.5-6 hours oral total. | ||
ReasoningReasoningExisting DB values (community consensus). Consistent with IPH's 10-fold CES1 resistance producing longer duration than MPH (2-4 hours). Article prose states 3.5-6 hours oral total. Evidence basis: community_consensus_large | |||
| After effectstrace | 1–4 hours | 1–4 hours | low |
| Editorial | Work-notes specify 1-4 hours aftereffects for oral. User reports describe next-day mood effects at higher doses. No human PK data. | ||
ReasoningReasoningWork-notes specify 1-4 hours aftereffects for oral. User reports describe next-day mood effects at higher doses. No human PK data. Evidence basis: community_consensus_large | |||
insufflated
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Onsettrace | 2–5 minutes | 2–5 minutes | low |
| Editorial | Existing DB values (community consensus). Rapid nasal absorption consistent with phenidate class. | ||
ReasoningReasoningExisting DB values (community consensus). Rapid nasal absorption consistent with phenidate class. Evidence basis: community_consensus_large | |||
| Come uptrace | 10–30 minutes | 10–30 minutes | low |
| Editorial | Existing DB values (community consensus). No human PK data. | ||
ReasoningReasoningExisting DB values (community consensus). No human PK data. Evidence basis: community_consensus_large | |||
| Peaktrace | 1–2 hours | 1–2 hours | low |
| Editorial | Existing DB values (community consensus). Shorter and more concentrated than oral peak. | ||
ReasoningReasoningExisting DB values (community consensus). Shorter and more concentrated than oral peak. Evidence basis: community_consensus_large | |||
| Offsettrace | 1–1.5 hours | 1–1.5 hours | low |
| Editorial | Existing DB values (community consensus). Relatively abrupt decline drives compulsive redosing. | ||
ReasoningReasoningExisting DB values (community consensus). Relatively abrupt decline drives compulsive redosing. Evidence basis: community_consensus_large | |||
| Totaltrace | 2.5–4 hours | 2.5–4 hours | low |
| Editorial | Existing DB values (community consensus). Shorter total duration than oral, consistent with faster absorption and metabolism kinetics. | ||
ReasoningReasoningExisting DB values (community consensus). Shorter total duration than oral, consistent with faster absorption and metabolism kinetics. Evidence basis: community_consensus_large | |||
| After effectstrace | 1–3 hours | 1–3 hours | low |
| Editorial | Work-notes specify 1-3 hours aftereffects for insufflated. Low mood more common than oral route per user reports. | ||
ReasoningReasoningWork-notes specify 1-3 hours aftereffects for insufflated. Low mood more common than oral route per user reports. Evidence basis: community_consensus_large | |||
Safety
Toxicity Profiletrace
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Acute | moderate | moderate | low |
| Chronic | moderate | moderate | low |
| Organs Affected | cardiovascular, neuropsychiatric | cardiovascular, neuropsychiatric | low |
| Editorial | All toxicity assessment is structural analog inference from methylphenidate. No IPH-specific toxicity, organ damage, or LD50 data exist. The 'moderate' acute and chronic ratings reflect DAT/NET reuptake inhibitor cardiovascular risk and stimulant psychosis potential without substance-specific confirmation. Evidence-discount rule applied: raw assessment would be 'moderate' from MPH data, maintained at 'moderate' because the pharmacological mechanism (DAT/NET inhibition) is directly confirmed for IPH, even though toxicity endpoints are not. | ||
ReasoningReasoningAll toxicity assessment is structural analog inference from methylphenidate. No IPH-specific toxicity, organ damage, or LD50 data exist. The 'moderate' acute and chronic ratings reflect DAT/NET reuptake inhibitor cardiovascular risk and stimulant psychosis potential without substance-specific confirmation. Evidence-discount rule applied: raw assessment would be 'moderate' from MPH data, maintained at 'moderate' because the pharmacological mechanism (DAT/NET inhibition) is directly confirmed for IPH, even though toxicity endpoints are not. Evidence basis: structural_analogy | |||
Dependence Profiletrace
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Physical | low | low | low |
| Psychological | moderate | moderate | low |
| Compulsive Redosing | moderate | moderate | low |
| Dose Escalation | moderate | moderate | low |
| Editorial | No formal dependence studies exist for IPH. Physical dependence downgraded from seed 'moderate' to 'low' per work-notes assessment — stimulant reuptake inhibitors typically produce minimal physical dependence. Psychological dependence rated 'moderate' from community consensus and DAT-mediated reinforcement mechanism. Compulsive redosing 'moderate' (work-notes say 'moderate-high', using 'moderate' as the enum value). All values are community-derived + class extrapolation from methylphenidate. | ||
ReasoningReasoningNo formal dependence studies exist for IPH. Physical dependence downgraded from seed 'moderate' to 'low' per work-notes assessment — stimulant reuptake inhibitors typically produce minimal physical dependence. Psychological dependence rated 'moderate' from community consensus and DAT-mediated reinforcement mechanism. Compulsive redosing 'moderate' (work-notes say 'moderate-high', using 'moderate' as the enum value). All values are community-derived + class extrapolation from methylphenidate. Evidence basis: community_consensus_large | |||
Withdrawal Profiletrace
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Severity | mild | mild | low |
| Symptoms | fatigue, hypersomnia, depression, anhedonia, reduced motivation, irritability | fatigue, hypersomnia, depression, anhedonia, reduced motivation, irritability | low |
| Fatal | No | No | low |
| Medical Supervision | Not required | Not required | low |
| Editorial | No published withdrawal data for IPH. Withdrawal profile inferred from stimulant class (methylphenidate, amphetamine). Stimulant withdrawal is characterized by fatigue, hypersomnia, depression, and anhedonia without severe physical symptoms or medical danger. Onset within 12-24 hours per class inference. | ||
ReasoningReasoningNo published withdrawal data for IPH. Withdrawal profile inferred from stimulant class (methylphenidate, amphetamine). Stimulant withdrawal is characterized by fatigue, hypersomnia, depression, and anhedonia without severe physical symptoms or medical danger. Onset within 12-24 hours per class inference. Evidence basis: community_consensus_large | |||
Tolerance Profiletrace
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Buildup | moderate | moderate | low |
| Half-life | 5 days | 5 days | low |
| Full Reset | 10.5 days | 10.5 days | low |
| Cross-tolerances | methylphenidate, amphetamines, cocaine, other dopaminergic stimulants | methylphenidate, amphetamines, cocaine, other dopaminergic stimulants | low |
| Editorial | Tolerance timeline values from existing DB (community consensus). Mechanism inferred from methylphenidate rodent studies (McNamara 1993). No IPH-specific tolerance studies exist. Cross-tolerances predicted from shared DAT mechanism but not directly confirmed for IPH. | ||
ReasoningReasoningTolerance timeline values from existing DB (community consensus). Mechanism inferred from methylphenidate rodent studies (McNamara 1993). No IPH-specific tolerance studies exist. Cross-tolerances predicted from shared DAT mechanism but not directly confirmed for IPH. Evidence basis: community_consensus_large | |||
Effects & Profile
Contraindications
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| metabolic Hyperthyroidismtrace | relative | relative | medium |
| Editorial | Class extrapolation from methylphenidate prescribing contraindications. Standard for all sympathomimetic stimulants. | ||
ReasoningReasoningClass extrapolation from methylphenidate prescribing contraindications. Standard for all sympathomimetic stimulants. | |||
| other Glaucomatrace | relative | relative | medium |
| Editorial | Class extrapolation from methylphenidate prescribing contraindications. No IPH-specific ocular data. | ||
ReasoningReasoningClass extrapolation from methylphenidate prescribing contraindications. No IPH-specific ocular data. | |||
| other MAOI usetrace | absolute | absolute | medium |
| Editorial | Class-level contraindication for all monoaminergic stimulants, extrapolated from methylphenidate prescribing guidelines. No IPH-specific data. | ||
ReasoningReasoningClass-level contraindication for all monoaminergic stimulants, extrapolated from methylphenidate prescribing guidelines. No IPH-specific data. | |||
| cardiovascular Severe cardiovascular diseasetrace | absolute | absolute | medium |
| Editorial | Class extrapolation from methylphenidate prescribing contraindications. IPH's reduced NET activity may attenuate cardiovascular effects relative to MPH, but this is unconfirmed in humans. | ||
ReasoningReasoningClass extrapolation from methylphenidate prescribing contraindications. IPH's reduced NET activity may attenuate cardiovascular effects relative to MPH, but this is unconfirmed in humans. | |||
| psychiatric Active psychosis or psychotic disorderstrace | absolute | absolute | medium |
| Editorial | Class extrapolation from methylphenidate and dopaminergic stimulant prescribing guidelines. No IPH-specific psychosis data published. | ||
ReasoningReasoningClass extrapolation from methylphenidate and dopaminergic stimulant prescribing guidelines. No IPH-specific psychosis data published. | |||
| psychiatric Anxiety disorderstrace | relative | relative | medium |
| Editorial | Class extrapolation from methylphenidate prescribing guidelines. IPH's DAT selectivity may reduce but not eliminate anxiogenic potential. | ||
ReasoningReasoningClass extrapolation from methylphenidate prescribing guidelines. IPH's DAT selectivity may reduce but not eliminate anxiogenic potential. | |||
| neurological Seizure disorderstrace | relative | relative | medium |
| Editorial | Class extrapolation from methylphenidate and stimulant class. No IPH-specific seizure data published. | ||
ReasoningReasoningClass extrapolation from methylphenidate and stimulant class. No IPH-specific seizure data published. | |||
| psychiatric History of substance use disorderstrace | relative | relative | medium |
| Editorial | Class extrapolation from methylphenidate abuse liability data. IPH-specific compulsive redosing noted in community reports. | ||
ReasoningReasoningClass extrapolation from methylphenidate abuse liability data. IPH-specific compulsive redosing noted in community reports. | |||
Timeline Phases
insufflated
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Afterglowtrace | 3600–10800 sec(i=0.15) | 3600–10800 sec(i=0.15) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. Evidence basis: community_consensus_large | |||
| Onsettrace | 120–300 sec(i=0.30) | 120–300 sec(i=0.30) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. Evidence basis: community_consensus_large | |||
| Come uptrace | 600–1800 sec(i=0.60) | 600–1800 sec(i=0.60) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. Evidence basis: community_consensus_large | |||
| Peaktrace | 3600–7200 sec(i=1.00) | 3600–7200 sec(i=1.00) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. Evidence basis: community_consensus_large | |||
| Resolutiontrace | 3600–5400 sec(i=0.35) | 3600–5400 sec(i=0.35) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 2-5 min, come_up 10-30 min, peak 1-2 hr, offset 1-1.5 hr, total 2.5-4 hr) and work-notes aftereffects estimate (1-3 hr). Intensity weights from work-notes. Insufflated ROA produces faster onset, shorter peak, and more abrupt offset than oral, driving compulsive redosing. No human PK data. Evidence basis: community_consensus_large | |||
oral
| Field | Published | AI Proposed | Confidence |
|---|---|---|---|
| Onsettrace | 600–1800 sec(i=0.15) | 600–1800 sec(i=0.15) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. Evidence basis: community_consensus_large | |||
| Come uptrace | 1200–2400 sec(i=0.45) | 1200–2400 sec(i=0.45) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. Evidence basis: community_consensus_large | |||
| Peaktrace | 5400–9000 sec(i=1.00) | 5400–9000 sec(i=1.00) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. Evidence basis: community_consensus_large | |||
| Resolutiontrace | 3600–7200 sec(i=0.40) | 3600–7200 sec(i=0.40) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. Evidence basis: community_consensus_large | |||
| Afterglowtrace | 3600–14400 sec(i=0.15) | 3600–14400 sec(i=0.15) | low |
| Editorial | Timeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. | ||
ReasoningReasoningTimeline derived from existing DB duration data (community consensus: onset 10-30 min, come_up 20-40 min, peak 1.5-2.5 hr, offset 1-2 hr, total 3.5-6 hr) and work-notes aftereffects estimate (1-4 hr). Intensity weights from work-notes. Consistent with rodent data showing sustained activity >120 min (Markowitz 2013). No human PK data exist. Evidence basis: community_consensus_large | |||
Dose Tier Summaries
Barely perceptible stimulation emerges as a subtle increase in alertness and wakefulness. There is no clear cognitive enhancement or mood elevation — effects may be difficult to distinguish from placebo or a mild caffeine response. Thought processes feel marginally sharper but without the directed focus enhancement characteristic of higher doses. Physical effects are negligible. There may be a faint awareness of increased heart rate or very mild appetite suppression, but these are subclinical and easily overlooked. Duration at this level is typically shorter than the full oral window. Sleep is generally unaffected if dosed early in the day.
No published human dose-response data for IPH. Threshold description derived from community consensus (PsychonautWiki, user reports) and structural analogy to methylphenidate threshold effects. Work-notes specify ~2 mg oral/insufflated threshold.
ReasoningReasoning
No published human dose-response data for IPH. Threshold description derived from community consensus (PsychonautWiki, user reports) and structural analogy to methylphenidate threshold effects. Work-notes specify ~2 mg oral/insufflated threshold.
Evidence basis: community_consensus_large
Mild cognitive enhancement becomes apparent — improved focus and sustained attention on tasks, slight motivation enhancement, and a gentle mood elevation that falls well short of euphoria. Thought acceleration is minimal but noticeable. The experience is functional and subtle, resembling a low therapeutic dose of methylphenidate. Appetite is mildly suppressed. Slight dry mouth may appear. Physical stimulation is modest — wakefulness increases without restlessness or noticeable cardiovascular effects. Vasoconstriction is typically absent at this level. Duration is somewhat shorter than common doses. Most users retain full functionality with minimal impairment of social naturalness.
Community consensus dose range (oral 5-15 mg, insufflated 5-10 mg). Effect profile inferred from user reports describing IPH as a functional, cognitively-focused stimulant with less physical push than methylphenidate at equivalent subjective doses.
ReasoningReasoning
Community consensus dose range (oral 5-15 mg, insufflated 5-10 mg). Effect profile inferred from user reports describing IPH as a functional, cognitively-focused stimulant with less physical push than methylphenidate at equivalent subjective doses.
Evidence basis: community_consensus_large
Clear functional stimulation defines this range — focus enhancement and motivation enhancement are reliably present, with thought acceleration producing a sense of cognitive flow. Cognitive euphoria is mild but recognizable, manifesting as satisfaction with task engagement rather than hedonic pleasure. Wakefulness is sustained and stable. Appetite suppression is noticeable. Dry mouth is common. Mild vasoconstriction may produce cool extremities. Stimulation is present but controlled — the physical profile is notably lighter than methylphenidate at equivalent cognitive effect levels, consistent with IPH's reduced NET activity. This is the dose range most commonly reported for productive use. Insufflation at this tier intensifies the compulsive redosing urge relative to oral dosing. Time alteration — typically a subtle sense that time passes quickly during focused work — may be noticed.
Community consensus dose range (oral 15-25 mg, insufflated 10-20 mg). Work-notes describe this as the primary functional use range. Effects profile drawn from user reports and pharmacological prediction (DAT-selective stimulation with reduced noradrenergic component).
ReasoningReasoning
Community consensus dose range (oral 15-25 mg, insufflated 10-20 mg). Work-notes describe this as the primary functional use range. Effects profile drawn from user reports and pharmacological prediction (DAT-selective stimulation with reduced noradrenergic component).
Evidence basis: community_consensus_large
Pronounced stimulation with increased peripheral effects. Cognitive enhancement may tip from productive focus into thought acceleration and mild thought disorganization. Motivation enhancement remains strong but may manifest as restless task-switching rather than sustained attention. Cognitive euphoria is more prominent but still modest compared to amphetamines. Physical effects intensify: tachycardia, bruxism, excessive sweating, and restlessness become likely. Vasoconstriction is more apparent. Appetite suppression is significant. The compulsive redosing urge becomes more prominent, particularly via insufflation. Post-effect irritability and depression are more likely at this tier. Insomnia is expected if dosed within 6-8 hours of intended sleep. Next-day cognitive fatigue and motivation suppression are commonly reported.
Community consensus dose range (oral 25-45 mg, insufflated 20-35 mg). Work-notes flag increased peripheral effects, compulsive redosing, and post-effect dysphoria. Effect escalation pattern inferred from methylphenidate dose-response and user reports.
ReasoningReasoning
Community consensus dose range (oral 25-45 mg, insufflated 20-35 mg). Work-notes flag increased peripheral effects, compulsive redosing, and post-effect dysphoria. Effect escalation pattern inferred from methylphenidate dose-response and user reports.
Evidence basis: community_consensus_large
Intense stimulation with significant cardiovascular strain — tachycardia, hypertension, and pronounced vasoconstriction. Risk of anxiety and paranoia increases substantially. At sustained high doses or with sleep deprivation, stimulant psychosis (paranoid ideation, referential thinking) becomes a real risk. Bruxism, tremor, and excessive sweating are likely. Cognitive effects overshoot productive enhancement — thought acceleration becomes uncomfortable, focus may fragment, and compulsive redosing urge is strong. The dopaminergic drive produces intense wanting without proportional hedonic reward, fueling repeated administration. Sleep is impossible for an extended period. Severe comedown is likely, featuring depression, irritability, anhedonia, and cognitive fatigue lasting into the following day. No LD50 data exist for IPH — the toxic dose ceiling is unknown, making dose escalation into this range particularly hazardous.
Community consensus heavy threshold (oral 45+ mg, insufflated 35+ mg). Work-notes flag significant cardiovascular strain, psychosis risk, and severe comedown. Overdose toxicology extrapolated from methylphenidate (Spiller 2013). No IPH-specific LD50 or toxic dose data exist.
ReasoningReasoning
Community consensus heavy threshold (oral 45+ mg, insufflated 35+ mg). Work-notes flag significant cardiovascular strain, psychosis risk, and severe comedown. Overdose toxicology extrapolated from methylphenidate (Spiller 2013). No IPH-specific LD50 or toxic dose data exist.
Evidence basis: community_consensus_large
History
backfill Jun 4, 2026
Historical versions do not record which reviewer approved them; editorial accountability is recorded per value in the database and in the publication ledger going forward.
Sources
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- [2]moderateOverdose of drugs for attention-deficit hyperactivity disorder: clinical presentation, mechanisms of toxicity, and management.Spiller HA, Hays HL, Aleguas A · 2013 · CNS Drugs
- [3]weakUS Patent US20120245201A1: Isopropylphenidate for Treatment of ADHD and Fatigue-Related DisordersMarkowitz JS · 2012linkno claims checked
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- [7]weakUK Temporary Class Drug Order: Methylphenidate-based NPS (ACMD Report, April 2015)Advisory Council on the Misuse of Drugs (ACMD) · 2015linkno claims checked
- [8]weakUNODC Early Warning Advisory: UK temporarily bans five methylphenidate-related NPS (April 2015)UNODC · 2015linkno claims checked
- [9]weakUK control of methylphenidate-based NPS: Misuse of Drugs (Amendment) Regulations 2017UK Home Office · 2017linkno claims checked
- [10]weakGermany NpSG: New Psychoactive Substances Act (Neue-psychoaktive-Stoffe-Gesetz) November 2016German Federal Government · 2016linkno claims checked
- [11]weakCanada Gazette: Amendments to Controlled Drugs and Substances Act Schedule III (methylphenidate analogues)Health Canada · 2017linkno claims checked
- [12]moderateSlow-onset, long-duration, alkyl analogues of methylphenidate with enhanced selectivity for the dopamine transporterFroimowitz M, Gu Y, Dakin LA, et al. · 2007 · Journal of Medicinal Chemistrypubmed 172288641 claim checked1 verified
- [13]moderateAnalysis of six 'neuro-enhancing' phenidate analogsKlare H, Neudörfl JM, Brandt SD, Mischler E, Meier-Giebing S, Deluweit K, Westphal F, Laussmann T · 2017 · Drug Testing and Analysis
- [14]moderatePharmacological profile of methylphenidate-based designer drugsLuethi D, Kaeser PJ, Brandt SD, Krähenbuhl S, Hoener MC, Liechti ME · 2018 · Neuropharmacology
- [15]moderateNovel psychoactive substances (designer drugs): overview and pharmacology of modulators of monoamine signalingLiechti ME · 2015 · Swiss Medical Weekly
- [16]moderateDifferential influences of ethanol on early exposure to racemic methylphenidate compared with dexmethylphenidate in humansPatrick KS, Straughn AB, Reeves OT, Bernstein H, Bell GH, Anderson ER, Malcolm RJ · 2013 · Drug Metabolism and Disposition
- [17]moderateUse of UPLC-HRMS/MS for In Vitro and In Vivo Metabolite Identification of Three Methylphenidate-derived New Psychoactive SubstancesManier SK, Niedermeier S, Schäper J, Meyer MR · 2020 · Journal of Analytical Toxicology
- [18]moderateIdentification of in vitro metabolites of ethylphenidate by liquid chromatography coupled to quadrupole time-of-flight mass spectrometryNegreira N, Erratico C, van Nuijs AL, Covaci A · 2016 · Journal of Pharmaceutical and Biomedical Analysis
- [19]moderateA comparison of the motor-activating effects of acute and chronic exposure to amphetamine and methylphenidateMcNamara CG, Davidson ES, Schenk S · 1993 · Pharmacology Biochemistry and Behaviorpubmed 83326313 claims checked3 verified
- [20]moderateThe Psychonauts' World of Cognitive EnhancersNapoletano F, Schifano F, Corkery JM, Guirguis A, Arillotta D, Zangani C, Vento A · 2020 · Frontiers in Psychiatry
- [21]weakSeven fatalities associated with ethylphenidate.Maskell PD, Smith PR, Cole R, Hikin L, Morley SR · 2016 · Forensic Science International
- [22]moderateTramadol: seizures, serotonin syndrome, and coadministered antidepressantsSansone RA, Sansone LA · 2009 · Psychiatry (Edgmont)pubmed 197247271 claim checked1 verified
- [23]moderateTramadol: Understanding the Risk of Serotonin Syndrome and SeizuresHassamal S, Miotto K, Dale W, Danovitch I · 2018 · The American Journal of Medicine
- [24]strongPharmacokinetic and pharmacodynamic effects of methylphenidate and MDMA administered alone or in combinationHysek CM, Simmler LD, Schillinger N, et al. · 2014 · International Journal of Neuropsychopharmacology
- [25]moderateEthylphenidate as a selective dopaminergic agonist and methylphenidate-ethanol transesterification biomarker.Patrick KS, Corbin TR, Murphy CE · 2014 · Journal of Pharmaceutical Sciences
- [26]moderateStimulant and hallucinogenic novel psychoactive substances; an updateSchifano F, Vento A, Scherbaum N, Guirguis A · 2023 · Expert Review of Clinical Pharmacology
- [27]moderateNemo censetur ignorare legem: what research chemists should know about the EU legal frameworkBianchi S, Campalani C, Vella V, Michel Q, Monbaliu J-CM · 2025 · Chemical Society Reviews
Claim Verification
Citation-bearing claims in this article were checked by an AI model against the abstract of the source they cite — every safety-critical claim, plus a sample of the rest. Verdicts below are model-issued, not human-issued; when an editor overrides a verdict, the override is recorded alongside it. Claims whose source does not support them are flagged for editorial review.
summary4 claims1partial3inconclusive
inconclusiveThis modification confers approximately 10-fold greater resistance to carboxylesterase-1 (CES1) hydrolysis relative to methylphenidate, producing a sustained stimulant profile with a total oral duration of 3.5–6 hours.[1]model confidence 88%
Abstract confirms CES1 resistance and sustained stimulant properties in rats, but neither the '10-fold' figure nor the '3.5–6 hour' oral duration are stated. Specific numbers require full text.
greater resistance to hydrolysis and transesterification via CES1 relative to MPH. Sustained psychostimulant properties in rats with locomotor activity as pharmacodynamic outcome.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveFirst reported in the chemical literature in 1961, isopropylphenidate remained pharmacologically uncharacterized until the foundational study by Markowitz, Zhu, and Patrick in 2013, which established its selective DAT inhibition, CES1 resistance, and reduced ethanol interaction liability[1]model confidence 85%
Abstract confirms this paper established DAT selectivity, CES1 resistance, and reduced drug interaction liability, but the 1961 origin date, author names, and year are not mentioned in the abstract.
IPH displayed greater DAT than NET binding and cellular uptake activity, greater resistance to hydrolysis and transesterification via CES1 relative to MPH.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveIPH blocks the dopamine transporter (DAT) with an IC₅₀ of approximately 200 nM while exhibiting markedly reduced norepinephrine transporter (NET) inhibition (IC₅₀ >10,000 nM), yielding a DAT-selective profile that distinguishes it from methylphenidate's more balanced DAT/NET action[1]model confidence 90%
Abstract confirms DAT > NET selectivity qualitatively, but the specific IC₅₀ values (200 nM, >10,000 nM) are not present. Full text required for numerical verification.
IPH displayed greater DAT than NET binding and cellular uptake activity.
checked by claude-sonnet-4-6 · May 12, 2026
partialAs a DAT/NET reuptake inhibitor, cardiovascular toxicity (tachycardia, hypertension) represents the primary acute risk at supratherapeutic doses, following the methylphenidate overdose profile[2]model confidence 82%
Abstract describes MPH overdose as featuring CNS symptoms (mydriasis, tremor, agitation, hyperreflexia, hallucinations, delirium, seizures) prominently, not cardiovascular effects as the 'primary' risk. Cardiovascular effects are not highlighted as primary.
MPH overdose features mydriasis, tremor, agitation, hyperreflexia, hallucinations, delirium, seizures. Mechanism: excessive DA/NE/5-HT.
checked by claude-sonnet-4-6 · May 12, 2026
history4 claims1verified3inconclusive
inconclusiveThe foundational pharmacological study was published by Markowitz, Zhu, and Patrick in 2013 in the Journal of Child and Adolescent Psychopharmacology[1]model confidence 85%
Abstract confirms the study's content matches but does not state the journal name, year, or authors. These bibliographic details require the full citation.
Investigated metabolic profiles and pharmacological activity of dl-isopropylphenidate (IPH) in vitro and in vivo.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveBy 2015, IPH had become established in the United Kingdom's novel psychoactive substance (NPS) market, functioning partly as a replacement for ethylphenidate following its scheduling[4]model confidence 78%
Abstract is a relevant review of methylphenidate analog NPS/cognitive enhancer use but does not specifically mention the 2015 UK market, EPH scheduling, or IPH as a replacement. Full text may contain this detail.
Review of use and misuse of methylphenidate analogs as NPS/cognitive enhancers.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveBy 2015, IPH had become established in the United Kingdom's novel psychoactive substance (NPS) market, functioning partly as a replacement for ethylphenidate following its scheduling[5]model confidence 75%
Abstract is a comprehensive NPS review covering phenidate analogs but does not confirm the 2015 UK market establishment or EPH replacement dynamic. This specific historical claim would require full text.
Comprehensive review of designer drugs mechanism of action and adverse effects across NPS classes.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedThe compound was adopted primarily by individuals seeking cognitive enhancement or self-medicating for ADHD symptoms.[6]model confidence 88%
Abstract confirms phenidate analogs among NPS primarily used for ADHD self-medication and cognitive enhancement via Reddit analysis.
Subjects mainly self-treating ADHD, anxiety, depression. 4F-MPH (a phenidate) among most discussed. Motivations include access, cost, legality, dissatisfaction with healthcare.
checked by claude-sonnet-4-6 · May 12, 2026
chemistry6 claims5verified1inconclusive
verifiedThis single substitution increases steric bulk and lipophilicity at the ester position, conferring resistance to enzymatic hydrolysis by carboxylesterase-1 (CES1).[1]model confidence 85%
Abstract confirms CES1 resistance, the functional endpoint of the structural mechanism described. The steric/lipophilicity explanation is the established reason for this resistance and the paper is the right citation.
greater resistance to hydrolysis and transesterification via CES1 relative to MPH.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedFroimowitz and colleagues systematically explored alkyl ester modifications to the methylphenidate scaffold, establishing that increased ester chain length and branching generally enhances DAT selectivity and prolongs duration of action.[12]model confidence 95%
Direct match: abstract confirms MPH alkyl ester analog testing showing slow onset, long duration, and enhanced DAT selectivity.
MPH analogues with alkyl ester substitutions tested in monoamine transporter assays. Some show slow onset and long duration with enhanced DAT selectivity.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedCommercial and research samples of IPH are prepared exclusively in the threo configuration[13]model confidence 95%
Abstract confirms exclusive threo-configuration for six phenidate analogs characterized.
Full characterization (X-ray, NMR, GC-MS, FTIR) of six phenidate analogs. Exclusive threo-configuration.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedThe racemic threo mixture (dl-IPH) was used in the Markowitz 2013 characterization[1]model confidence 97%
Abstract explicitly refers to 'dl-isopropylphenidate (IPH)', confirming the racemic mixture was studied.
Investigated metabolic profiles and pharmacological activity of dl-isopropylphenidate (IPH) in vitro and in vivo.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveIsopropylphenidate hydrochloride is a white crystalline powder[13]model confidence 82%
Abstract describes full characterization of phenidate analogs but does not state the physical appearance ('white crystalline powder'). This would be in the characterization data section of the full paper.
Full characterization (X-ray, NMR, GC-MS, FTIR) of six phenidate analogs.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedPhenidate analogs as a class exhibit thermal instability under gas chromatography–mass spectrometry (GC-MS) conditions, with decomposition occurring in the injection port; liquid chromatography–tandem mass spectrometry (LC-MS/MS) is therefore the preferred analytical method for forensic identification.[13]model confidence 95%
Abstract explicitly states 'Thermal decomposition in GC-MS' for phenidate analogs, directly supporting the claim about GC-MS instability and the preference for alternative methods.
Full characterization (X-ray, NMR, GC-MS, FTIR) of six phenidate analogs. Thermal decomposition in GC-MS.
checked by claude-sonnet-4-6 · May 12, 2026
pharmacology13 claims6verified7inconclusive
inconclusiveIt has negligible activity at the serotonin transporter (SERT)[1]model confidence 90%
Abstract does not mention SERT at all; only DAT and NET are referenced. SERT data would require full text.
IPH displayed greater DAT than NET binding and cellular uptake activity.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveIt has negligible activity at the serotonin transporter (SERT)[14]model confidence 85%
Abstract confirms SERT characterization was performed for multiple phenidate analogs including IPH, but does not state the specific SERT result for IPH (negligible vs. detectable activity).
Characterizes DAT/NET/SERT binding and uptake inhibition, monoamine release, and cytotoxicity data for multiple phenidate analogs.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveThis mechanistic distinction separates the phenidate class from amphetamine-class stimulants, which induce reverse transport (efflux) of monoamines through the transporter.[15]model confidence 80%
Abstract discusses DAT/serotonin transporter inhibition ratios and NPS pharmacology broadly but does not explicitly describe reverse transport/efflux by amphetamines. Full text likely covers this.
Dopamine/serotonin transporter inhibition ratio predicts psychotropic vs toxic effects.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveIn vitro transesterification rates demonstrate approximately 10-fold slower CES1 metabolism for IPH (47.5 ± 3.3 pmol/min/mg protein) compared to methylphenidate (423.3 ± 44.4 pmol/min/mg protein)[1]model confidence 90%
Abstract confirms CES1 resistance qualitatively but the specific pmol/min/mg values (47.5 and 423.3) are not present; they would be in the full text results table.
greater resistance to hydrolysis and transesterification via CES1 relative to MPH.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedThis resistance has two major consequences: sustained pharmacological action beyond methylphenidate's typical 2–3 hour effective window, and substantially reduced ethanol interaction via the CES1-mediated transesterification pathway that converts methylphenidate to ethylphenidate in the presence of alcohol.[1]model confidence 88%
Abstract confirms both CES1 resistance (underpinning reduced ethanol interaction) and sustained stimulant properties in vivo. The 2–3 hour MPH window is not stated but the sustained activity finding and reduced drug interaction liability directly support both claimed consequences.
greater resistance to hydrolysis and transesterification via CES1 relative to MPH. Sustained psychostimulant properties in rats with locomotor activity as pharmacodynamic outcome.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedThis resistance has two major consequences: sustained pharmacological action beyond methylphenidate's typical 2–3 hour effective window, and substantially reduced ethanol interaction via the CES1-mediated transesterification pathway that converts methylphenidate to ethylphenidate in the presence of alcohol.[16]model confidence 92%
Abstract directly covers CES1-mediated enantioselective hydrolysis and transesterification of MPH with ethanol, confirming the mechanistic basis for the ethanol interaction pathway.
CES1-mediated enantioselective hydrolysis and transesterification. Relevant to IPH's reduced CES1 hydrolysis and reduced ethanol interaction risk.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveIn rats, intraperitoneal administration of IPH at 10 mg/kg produced locomotor stimulation with onset within approximately 10 minutes and sustained elevation over 120 minutes, consistent with the prolonged CES1 resistance profile and exceeding the duration of equivalent methylphenidate doses.[1]model confidence 88%
Abstract confirms rat locomotor data as pharmacodynamic outcome, but the specific dose (10 mg/kg), onset time (~10 min), and duration (120 min) are not stated. Full text required.
Sustained psychostimulant properties in rats with locomotor activity as pharmacodynamic outcome.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedManier and colleagues identified 17 metabolites of IPH in rat urine using ultra-high-performance liquid chromatography–high-resolution tandem mass spectrometry (UHPLC-HRMS/MS): 14 phase I metabolites and 3 phase II metabolites[17]model confidence 98%
Direct match: abstract states 'Identified 17 metabolites of IPH (14 phase I, 3 phase II) in rat urine using UHPLC-HRMS/MS.'
Identified 17 metabolites of IPH (14 phase I, 3 phase II) in rat urine using UHPLC-HRMS/MS.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusivePhase I oxidative metabolism (hydroxylation at multiple positions) and phase II conjugation (glucuronidation) also occur[17]model confidence 85%
Abstract confirms 14 phase I and 3 phase II metabolites but does not specify the types (hydroxylation, glucuronidation). Those details would be in the full text.
Identified 17 metabolites of IPH (14 phase I, 3 phase II) in rat urine using UHPLC-HRMS/MS.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedCarboxy metabolites are recommended as analytical targets alongside the parent compound for toxicological screening.[17]model confidence 98%
Direct match: abstract states 'Carboxy metabolites recommended as additional analytical targets for comprehensive screening.'
Carboxy metabolites recommended as additional analytical targets for comprehensive screening.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedBy analogy with ethylphenidate, the closest well-studied phenidate analog, CYP2C19 is likely the most active oxidative isoform, with contributions from CYP1A2, CYP2B6, CYP2C9, CYP2D6, and CYP3A4.[18]model confidence 95%
Abstract directly confirms CYP2C19 as most active for EPH, with rCYP1A2, 2B6, 2C9, 2D6, 3A4 also involved. Claim appropriately frames this as analogical inference.
CYP2C19 most active. rCYP1A2, 2B6, 2C9, 2D6, 3A4 also involved.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveMethylphenidate's oral bioavailability is approximately 30% for d-methylphenidate due to extensive CES1-mediated presystemic hydrolysis[16]model confidence 88%
Abstract covers CES1-mediated hydrolysis of MPH but does not state the ~30% oral bioavailability figure. That data would be in the full text or methods section.
CES1-mediated enantioselective hydrolysis and transesterification.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedThe duration data available (oral total 3.5–6 hours, insufflated total 2.5–4 hours) derive exclusively from user self-reports and are consistent with the animal data demonstrating sustained activity relative to methylphenidate.[1]model confidence 90%
Abstract confirms sustained psychostimulant activity in rats relative to MPH, which the claim uses as the animal-data comparison point. The claim correctly identifies the user-report origin of the duration figures.
Sustained psychostimulant properties in rats with locomotor activity as pharmacodynamic outcome.
checked by claude-sonnet-4-6 · May 12, 2026
receptor pharmacology5 claims3verified2inconclusive
verifiedThe primary pharmacological characterization of isopropylphenidate derives from Markowitz and colleagues, who assessed monoamine transporter inhibition using rat synaptosome and HEK293 transfected cell assays.[1]model confidence 87%
Abstract confirms this paper performed in vitro and in vivo pharmacological characterization of IPH. Specific assay types (rat synaptosome, HEK293) are not stated in the abstract but this is clearly the primary characterization paper.
Investigated metabolic profiles and pharmacological activity of dl-isopropylphenidate (IPH) in vitro and in vivo.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedMarkowitz and colleagues concluded that IPH exhibits "greater DAT than NET binding and cellular uptake activity," qualitatively confirming selective dopaminergic action over noradrenergic. The specific IC₅₀ values (DAT ~200 nM, NET >10,000 nM) are aggregated from secondary sources citing Markowitz 2013; full-text verification of these exact numerical values is required.[1]model confidence 97%
The quoted phrase 'greater DAT than NET binding and cellular uptake activity' appears verbatim in the abstract. The claim also appropriately flags the IC₅₀ values as needing full-text verification.
IPH displayed greater DAT than NET binding and cellular uptake activity.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedLuethi and colleagues characterized the pharmacological profile of IPH and related methylphenidate-based designer drugs in vitro using HEK293 cells transfected with human DAT, NET, and SERT[14]model confidence 90%
Abstract confirms in vitro DAT/NET/SERT characterization of methylphenidate-based NPS including IPH. HEK293 cell type not specified in abstract but full characterization is confirmed.
In vitro pharmacological characterization of methylphenidate-based NPS including IPH. Characterizes DAT/NET/SERT binding and uptake inhibition.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveAt the standard 10 µM screening concentration, methylphenidate inhibits NET with approximately 88% efficiency, while isopropylphenidate achieves only approximately 62% — and at lower concentrations the disparity widens further, with IPH showing approximately 27% NET inhibition versus methylphenidate's maintained high inhibition[1]model confidence 90%
Abstract confirms DAT > NET selectivity for IPH but provides no specific inhibition percentages (88%, 62%, 27%). These figures would require full text data tables.
IPH displayed greater DAT than NET binding and cellular uptake activity.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveThe phenidate class is generally considered selective for monoamine transporters without significant off-target receptor activity, but IPH-specific receptor profiling panels have not been published.[15]model confidence 78%
Abstract discusses monoamine transporter pharmacology generally but does not confirm specificity without off-target activity or comment on the absence of IPH-specific profiling panels.
Overview of NPS pharmacology and classification. Dopamine/serotonin transporter inhibition ratio predicts psychotropic vs toxic effects.
checked by claude-sonnet-4-6 · May 12, 2026
neuroscience2 claims2verified
verifiedChronic methylphenidate administration in rodents produces tolerance to locomotor effects rather than sensitization — a pattern that distinguishes phenidates from amphetamines, which characteristically produce behavioral sensitization with repeated dosing[19]model confidence 98%
Direct match: abstract states chronic MPH produces tolerance to locomotor activity (not sensitization like amphetamine), distinguishing reuptake blockers from releasers.
Chronic MPH administration produces tolerance to locomotor activity (not sensitization like amphetamine). Suggests different mechanisms of tolerance development between reuptake blockers and releasers.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedIs the tolerance profile (tolerance without sensitization) confirmed in primates or humans? The rat data from McNamara 1993 apply to methylphenidate; IPH-specific tolerance neuroadaptation is unstudied.[19]model confidence 93%
Abstract confirms this is rodent data on MPH, validating the claim's caveat that the tolerance profile is from rat studies of methylphenidate, not primates, humans, or IPH specifically.
Chronic MPH administration produces tolerance to locomotor activity (not sensitization like amphetamine). Suggests different mechanisms of tolerance development between reuptake blockers and releasers.
checked by claude-sonnet-4-6 · May 12, 2026
pharmacokinetic detail2 claims2verified
verifiedStructural analog inference from ethylphenidate suggests CYP2C19 as the primary oxidative isoform, with secondary contributions from CYP1A2, CYP2B6, CYP2C9, CYP2D6, and CYP3A4. Individuals who are CYP2C19 poor metabolizers may experience prolonged effects if this isoform is relevant to IPH oxidative metabolism, but this has not been studied.[18]model confidence 95%
Abstract confirms CYP2C19 as most active for EPH with rCYP1A2, 2B6, 2C9, 2D6, 3A4 also involved. The inference from EPH to IPH is appropriate and the caveat about lack of IPH-specific study is accurate.
CYP2C19 most active. rCYP1A2, 2B6, 2C9, 2D6, 3A4 also involved.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedCYP-mediated drug interactions are likely less clinically significant given that oxidative metabolism appears to be a secondary pathway[17]model confidence 88%
Abstract confirms that hydrolysis (not CYP oxidation) is the primary pathway ('primary hydrolysis to carboxy metabolites'), supporting that CYP-mediated interactions are secondary.
Human S9 fraction indicated primary hydrolysis to carboxy metabolites.
checked by claude-sonnet-4-6 · May 12, 2026
clinical evidence5 claims3verified2inconclusive
inconclusiveDespite the 2013 Markowitz study concluding that IPH "warrant[ed] further study and development as a novel psychotherapeutic agent" and the filing of a US patent proposing IPH for ADHD and fatigue-related disorders with a dosing range of 10–100 mg per dose, no Phase I safety, Phase II efficacy, or Phase III confirmatory trials have been initiated.[1]model confidence 82%
Abstract confirms the pharmacological study but does not contain the quoted conclusion, patent information, dosing range, or trial status. These details are in the full text and external records.
Investigated metabolic profiles and pharmacological activity of dl-isopropylphenidate (IPH) in vitro and in vivo.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveThe sole published in vivo study is the Markowitz 2013 rat locomotor assay, which demonstrated sustained stimulant activity at 10 mg/kg intraperitoneal with onset within approximately 10 minutes and elevation maintained over 120 minutes[1]model confidence 88%
Abstract confirms rat locomotor pharmacodynamic data but not the specific 10 mg/kg dose, 10-min onset, or 120-min duration. Full text required for these figures.
Sustained psychostimulant properties in rats with locomotor activity as pharmacodynamic outcome.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedManier and colleagues conducted in vitro metabolite identification using rat urine and human S9 fractions, establishing the metabolic profile for forensic and clinical analytical purposes[17]model confidence 97%
Direct match: abstract confirms rat urine and human S9 fraction methodology for metabolite identification of IPH.
Identified 17 metabolites of IPH (14 phase I, 3 phase II) in rat urine using UHPLC-HRMS/MS. Human S9 fraction indicated primary hydrolysis to carboxy metabolites.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedIn the absence of clinical evidence, isopropylphenidate has been adopted by individuals self-medicating for ADHD symptoms and cognitive enhancement, a pattern documented in qualitative research on novel psychoactive substance use[6]model confidence 92%
Abstract directly documents ADHD self-medication with phenidate NPS (including 4F-MPH) via Reddit qualitative analysis, confirming the pattern described.
Subjects mainly self-treating ADHD, anxiety, depression. 4F-MPH (a phenidate) among most discussed. Motivations include access, cost, legality, dissatisfaction with healthcare.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedIn the absence of clinical evidence, isopropylphenidate has been adopted by individuals self-medicating for ADHD symptoms and cognitive enhancement, a pattern documented in qualitative research on novel psychoactive substance use[20]model confidence 92%
Abstract confirms phenidate analogs among NPS used for cognitive enhancement in psychonaut/internet communities, directly supporting the documented pattern.
Growing availability of NPS as cognitive enhancers. Internet/psychonaut-reported use patterns. Identifies phenidate analogs among commonly reported cognitive enhancers.
checked by claude-sonnet-4-6 · May 12, 2026
safety11 claims10verified1inconclusive
verifiedThe closely related ethylphenidate has been associated with 7 documented fatalities, establishing that phenidate-class analogs carry real toxicity risk despite the absence of IPH-specific fatality data.[21]model confidence 97%
Direct match: 7 EPH postmortem cases confirmed (ages 23–49, male), including sole EPH toxicity cases and mixed drug toxicity, establishing real phenidate-class risk.
7 cases with ethylphenidate (EPH) detected in postmortem blood (Feb 2013-Jan 2015). All male, ages 23-49. One case sole EPH toxicity; 4 mixed drug toxicity; 2 hangings.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedGiven IPH's mechanism as a DAT/NET reuptake inhibitor, its acute overdose toxicology is expected to parallel methylphenidate overdose presentations. Anticipated features include:[2]model confidence 92%
Abstract provides MPH overdose clinical features (mydriasis, tremor, agitation, hyperreflexia, hallucinations, delirium, seizures) that form the direct basis for the IPH inference.
MPH overdose features mydriasis, tremor, agitation, hyperreflexia, hallucinations, delirium, seizures. Mechanism: excessive DA/NE/5-HT.
checked by claude-sonnet-4-6 · May 12, 2026
verified{{Emergency}}In suspected isopropylphenidate overdose, management follows methylphenidate/stimulant overdose protocol: benzodiazepines as first-line treatment for agitation and seizures, supportive cardiovascular management, continuous temperature monitoring, and poison control consultation.{{/Emergency}}[2]model confidence 90%
Abstract explicitly states benzodiazepines as first-line management for MPH overdose. Supportive cardiovascular management and monitoring are standard extensions of this protocol supported by the DA/NE/5-HT mechanism described.
Management: benzodiazepines first-line; antipsychotics for refractory cases.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedTolerance to stimulant effects is expected with repeated administration, following the methylphenidate pattern of locomotor tolerance without behavioral sensitization[19]model confidence 97%
Direct match: abstract states chronic MPH produces tolerance to locomotor activity (not sensitization like amphetamine).
Chronic MPH administration produces tolerance to locomotor activity (not sensitization like amphetamine).
checked by claude-sonnet-4-6 · May 12, 2026
verifiedIPH's slower CES1 metabolism may confer somewhat reduced abuse liability compared to methylphenidate by reducing the rapid rise-and-fall plasma kinetics that drive reinforcement cycles[1]model confidence 82%
Abstract confirms slower CES1 metabolism and sustained stimulant action. The abuse liability inference follows directly from the pharmacokinetic profile established in this paper.
greater resistance to hydrolysis and transesterification via CES1 relative to MPH. Sustained psychostimulant properties in rats.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveUser community reports describe psychological dependence tied primarily to productivity-enhancement contexts (ADHD self-medication), with compulsive redosing urge as a notable feature.[6]model confidence 78%
Abstract confirms ADHD self-medication as a primary motivation for NPS use, but 'compulsive redosing urge' is not mentioned. IPH is not specifically cited; 4F-MPH is highlighted. Full text may contain relevant content.
Subjects mainly self-treating ADHD, anxiety, depression. 4F-MPH (a phenidate) among most discussed.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedTramadol inhibits serotonin and norepinephrine reuptake (SNRI-like action) and significantly lowers the seizure threshold[22]model confidence 97%
Direct match: abstract states tramadol inhibits serotonin and norepinephrine reuptake with seizures as a significant adverse reaction.
Tramadol inhibits serotonin and norepinephrine reuptake; seizures and serotonin syndrome are two significant adverse reactions.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedTramadol inhibits serotonin and norepinephrine reuptake (SNRI-like action) and significantly lowers the seizure threshold[23]model confidence 97%
Direct match: abstract confirms tramadol's SNRI activity underlies serotonin syndrome and seizure risks.
Tramadol's SNRI activity underlies serotonin syndrome and seizure risks.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedA human randomized controlled trial demonstrated that methylphenidate (0.5 mg/kg) combined with MDMA (125 mg) produced significantly elevated cardiovascular adverse effects (heart rate, blood pressure) compared to either drug alone, without enhancement of desired subjective effects[24]model confidence 93%
Abstract confirms MPH+MDMA significantly enhances cardiovascular and adverse effects without increasing psychoactive effects. Specific doses are not confirmed in the abstract but the core finding matches.
MPH+MDMA in healthy subjects: combination does not increase psychoactive effects but significantly enhances cardiovascular and adverse effects compared to either alone.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedIPH's 10-fold CES1 resistance substantially reduces the transesterification pathway (methylphenidate + ethanol → ethylphenidate) that represents a pharmacokinetic drug interaction specific to methylphenidate[1]model confidence 90%
Abstract confirms IPH's greater resistance to transesterification via CES1, directly supporting reduced risk of this pathway.
greater resistance to hydrolysis and transesterification via CES1 relative to MPH.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedIPH's 10-fold CES1 resistance substantially reduces the transesterification pathway (methylphenidate + ethanol → ethylphenidate) that represents a pharmacokinetic drug interaction specific to methylphenidate[16]model confidence 92%
Abstract directly covers CES1-mediated transesterification of MPH with ethanol, confirming the pharmacokinetic mechanism that IPH's CES1 resistance reduces.
CES1-mediated enantioselective hydrolysis and transesterification. Relevant to IPH's reduced CES1 hydrolysis and reduced ethanol interaction risk.
checked by claude-sonnet-4-6 · May 12, 2026
comparative pharmacology9 claims3verified6inconclusive
verifiedEPH has been associated with 7 documented fatalities, while no fatalities have been attributed to IPH[21]model confidence 95%
Abstract directly confirms 7 EPH postmortem cases. No IPH fatalities is a negative claim not requiring this citation to support it.
7 cases with ethylphenidate (EPH) detected in postmortem blood (Feb 2013-Jan 2015).
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveAt 10 µM, methylphenidate inhibits NET with approximately 88% efficiency versus IPH's approximately 62%[1]model confidence 90%
Abstract confirms DAT > NET selectivity for IPH but no specific inhibition percentages are stated. Full text data required.
IPH displayed greater DAT than NET binding and cellular uptake activity.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveCES1 resistance: IPH's transesterification rate is approximately 10-fold slower than methylphenidate's (47.5 vs 423.3 pmol/min/mg protein), producing a longer effective duration.[1]model confidence 90%
Abstract confirms 10-fold CES1 resistance qualitatively but the specific pmol/min/mg values (47.5, 423.3) are not present in the abstract.
greater resistance to hydrolysis and transesterification via CES1 relative to MPH.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveEthanol interaction: Methylphenidate undergoes CES1-mediated transesterification with ethanol to form ethylphenidate, which potentiates euphoria and abuse liability[16]model confidence 82%
Abstract confirms CES1-mediated transesterification of MPH with ethanol, but does not state that ethylphenidate formed in this way potentiates euphoria or abuse liability. That specific claim requires full text or another source.
CES1-mediated enantioselective hydrolysis and transesterification.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveEthanol interaction: Methylphenidate undergoes CES1-mediated transesterification with ethanol to form ethylphenidate, which potentiates euphoria and abuse liability[25]model confidence 82%
Abstract confirms CES1 transesterification of MPH with ethanol forming EPH, but does not explicitly state that this potentiates euphoria or abuse liability.
CES1 transesterification of MPH with ethanol.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedEthylphenidate (EPH) shares IPH's enhanced DAT selectivity but differs in metabolic stability and safety profile. d-EPH shows near-exclusive DAT action with minimal NET involvement[25]model confidence 92%
Abstract directly confirms d-EPH selectively targets DAT, supporting the near-exclusive DAT action claim.
d-EPH selectively targets DAT; CES1 transesterification of MPH with ethanol.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveThe fundamental mechanistic distinction is that IPH is a reuptake inhibitor (blocks transporter clearance) while amphetamines are releasing agents (induce reverse transport/efflux)[15]model confidence 78%
Abstract discusses DAT/serotonin transporter inhibition ratios and NPS pharmacology broadly but does not explicitly describe the reuptake inhibitor vs. releasing agent distinction or reverse transport/efflux.
Overview of NPS pharmacology and classification. Dopamine/serotonin transporter inhibition ratio predicts psychotropic vs toxic effects.
checked by claude-sonnet-4-6 · May 12, 2026
inconclusiveWithin the broader novel psychoactive stimulant landscape, IPH is notable for its relatively clean pharmacological profile (selective DAT inhibition without releasing activity, serotonergic effects, or off-target receptor binding), its sustained duration, and its reduced ethanol interaction liability[26]model confidence 78%
Abstract covers phenidates as a distinct NPS class in an updated review, but does not specifically describe IPH's 'clean profile,' releasing activity absence, or ethanol interaction liability.
Updated overview of stimulant and psychedelic NPS pharmacology and clinical risks. Covers phenidates as a distinct NPS class.
checked by claude-sonnet-4-6 · May 12, 2026
verifiedWithin the broader novel psychoactive stimulant landscape, IPH is notable for its relatively clean pharmacological profile (selective DAT inhibition without releasing activity, serotonergic effects, or off-target receptor binding), its sustained duration, and its reduced ethanol interaction liability[5]model confidence 83%
Abstract confirms phenidate analogs interact primarily with monoamine transporters (not serotonergic or other receptor systems), supporting the 'clean profile' characterization within the NPS landscape.
Stimulants including phenidate analogs interact primarily with monoamine transporters, causing sympathomimetic adverse effects.
checked by claude-sonnet-4-6 · May 12, 2026
Coverage & Gaps
Research Trail
substance-article pipeline-v5 May 11, 2026
| Step | Source | Query | Results |
|---|---|---|---|
| 1database lookup | PubChem | isopropylphenidate | 1 result, 1 selected |
selection rationaleselection rationalePrimary chemical identity data for isopropylphenidate discarded 0: no summary recorded | |||
| 2literature search | PubMed | isopropylphenidate pharmacology | 5 results, 4 selected |
selection rationaleselection rationaleAll directly relevant to IPH pharmacology and toxicology discarded 1: no summary recorded | |||
| 3literature search | PubMed | isopropylphenidate IPH stimulant | 2 results, 2 selected |
selection rationaleselection rationaleAlready captured; no new results discarded 0: no summary recorded | |||
| 4clinical trial search | ClinicalTrials.gov | isopropylphenidate | 0 results, 0 selected |
selection rationaleselection rationaleNo trials exist; gap to note in output discarded 0: no summary recorded | |||
| 5literature search | PubMed | methylphenidate carboxylesterase hydrolysis ethanol transesterification | 2 results, 1 selected |
selection rationaleselection rationaleRelevant to IPH's reduced CES1 interaction advantage discarded 1: no summary recorded | |||
| 6literature search | OpenAlex | isopropylphenidate pharmacology dopamine | 10 results, 4 selected |
selection rationaleselection rationaleProvide NPS class context and adverse effect profiles for phenidates discarded 6: no summary recorded | |||
| 7literature search | OpenAlex | methylphenidate phenidate new psychoactive substances forensic detection | 10 results, 4 selected |
selection rationaleselection rationalePhenidate class forensic characterization, safety context, and comparative pharmacology discarded 6: no summary recorded | |||
| 8web search | WebSearch | isopropylphenidate legal status scheduling UK US EU Australia 2024 | 10 results, 4 selected |
selection rationaleselection rationaleLegal status data for major jurisdictions discarded 6: no summary recorded | |||
| 9web search | WebSearch | isopropylphenidate Canada Schedule III controlled drugs substances | 10 results, 1 selected |
selection rationaleselection rationaleCanada scheduling confirmed discarded 9: no summary recorded | |||
| 10web search | WebSearch (via Grokipedia) | isopropylphenidate pharmacological data | 1 result, 3 selected |
selection rationaleselection rationaleSpecific binding data sourced from Markowitz 2013 paper - web retrieval only, cannot access full text directly discarded 0: no summary recorded | |||
| 11document retrieval | PubMed/Crossref DOI verification | DOI 10.1089/cap.2013.0074 | 1 result, 1 selected |
selection rationaleselection rationaleVerification of primary pharmacology paper discarded 0: no summary recorded | |||
| 12literature search | PubMed | methylphenidate MDMA co-administration interaction serotonin cardiovascular | 1 result, 1 selected |
selection rationaleselection rationaleDirect evidence for MPH-class+MDMA dangerous cardiovascular interaction discarded 0: no summary recorded | |||
| 13literature search | PubMed | methylphenidate adverse effects cardiovascular hypertension clinical review | 4 results, 2 selected |
selection rationaleselection rationaleOverdose management and cardiovascular data directly applicable to IPH as MPH analog discarded 2: no summary recorded | |||
| 14web search | WebSearch | stimulant tramadol dangerous interaction seizure serotonin | 10 results, 2 selected |
selection rationaleselection rationaleMechanism for tramadol 'lethal' interaction with IPH discarded 8: no summary recorded | |||
| 15cross reference | Multiple sources | Verification of chemical data against PubChem and secondary sources | 3 results, 3 selected |
selection rationaleselection rationaleChemical identity cross-verification discarded 0: no summary recorded | |||
| 16data extraction | Grokipedia (web_retrieved) | isopropylphenidate binding affinity specific values | 1 result, 3 selected |
selection rationaleselection rationaleOnly available numerical binding data; flagged as requiring full-text verification discarded 0: no summary recorded | |||
| 17legal status search | WebSearch | isopropylphenidate legal status UK US Germany Canada Australia | 20 results, 3 selected |
selection rationaleselection rationaleLegal status across major jurisdictions discarded 15: no summary recorded | |||
Research document (raw, unedited pipeline output)
# Research Output: Isopropylphenidate
## Chemical Identity
**Verified from PubChem CID 68314762 [Ref 1 — database lookup]:**
| Property | Value |
|---|---|
| Molecular Formula | C₁₆H₂₃NO₂ |
| Molecular Weight | 261.36 g/mol |
| IUPAC Name | propan-2-yl 2-phenyl-2-piperidin-2-ylacetate |
| InChIKey | AZVPADMEIMLODT-UHFFFAOYSA-N |
| PubChem CID | 68314762 |
**Additional identifiers from web-retrieved sources [web_retrieved]:**
- Canonical SMILES: `CC(C)OC(=O)C(C1CCCCN1)C2=CC=CC=C2`
- CAS Number (free base): 93148-45-9
- CAS Number (threo-HCl salt): 1262795-94-7
**Discrepancy with seed data:** The brief lists no SMILES, formula, weight, or PubChem CID. These are now confirmed from PubChem. The IUPAC name in the brief ("propan-2-yl 2-phenyl-2-piperidin-2-ylacetate") matches PubChem exactly.
**Structural relationship:** Isopropylphenidate (IPH) is the isopropyl ester homolog of methylphenidate (MPH), differing by substitution of the methyl ester group with an isopropyl ester. The increased steric bulk and lipophilicity of the isopropyl group confers resistance to enzymatic hydrolysis by carboxylesterase 1 (CES1) relative to MPH [Ref 1, Ref 2].
**Physical form:** White crystalline powder, exclusively threo-configuration (as with other phenidate analogs characterized by X-ray crystallography) [Ref 7].
---
## Pharmacology
### Mechanism of Action
Isopropylphenidate functions as a dopamine reuptake inhibitor (DRI) with secondary, weaker norepinephrine reuptake inhibition. It blocks the dopamine transporter (DAT) and, to a lesser extent, the norepinephrine transporter (NET), increasing synaptic concentrations of dopamine and norepinephrine. It has negligible activity at the serotonin transporter (SERT) [Ref 1, Ref 2].
IPH is a reuptake *inhibitor*, not a releasing agent — it does not stimulate monoamine efflux through the transporter, which is mechanistically distinct from amphetamine-class drugs [Ref 6]. This mechanism is shared with methylphenidate and ethylphenidate.
### Binding Affinities
From Markowitz et al. (2013 [Ref 1]) in vitro data (rat synaptosome / HEK293 transfected cell assays):
| Target | IPH IC₅₀ | Inhibition at 10 µM | Comparison to MPH |
|---|---|---|---|
| DAT (uptake inhibition) | ~200 nM | ~96–97% | Comparable to MPH |
| NET (uptake inhibition) | >10,000 nM | ~62% | Markedly lower than MPH (~88% at same concentration) |
| SERT (binding inhibition) | Not determined | ~20% at 10 µM | Negligible |
**FLAG:** The specific IC₅₀ and Ki values are not directly accessible from the published abstract — the values above are aggregated from secondary sources (Grokipedia citing Markowitz 2013; web-retrieved). Exact numerical values in the primary paper require full-text access. This warrants editorial confirmation.
Markowitz et al. (2013 [Ref 1]) explicitly concluded that IPH exhibits "greater DAT than NET binding and cellular uptake activity" — qualitatively confirming selective dopaminergic action over noradrenergic.
Luethi et al. (2018 [Ref 3]) characterized the pharmacological profile of IPH and related methylphenidate-based designer drugs in vitro, using HEK293 cells transfected with human DAT, NET, and SERT. Specific Ki or IC₅₀ values for IPH from this paper were not accessible in full text; the abstract confirms the study characterizes IPH's monoaminergic transporter pharmacology. **FLAG: Full-text access to Luethi 2018 is required to obtain the specific quantitative binding data from that paper.**
### DAT/NET Selectivity
IPH exhibits substantially greater DAT selectivity than MPH. MPH inhibits NET with ~88% efficiency at 10 µM, while IPH produces only ~27% NET inhibition at the same concentration. This enhanced DAT/NET selectivity ratio may reduce noradrenergic adverse effects (e.g., hypertension, palpitations) relative to MPH, though no human data confirm this prediction [Ref 1].
By contrast, ethylphenidate (EPH) exhibits even greater DAT selectivity, with d-EPH showing near-exclusive DAT action [Ref 12].
### Metabolic Pharmacology — CES1 Resistance
A key pharmacological distinction of IPH over MPH is its markedly greater resistance to CES1-mediated hydrolysis. The transesterification rate for IPH is approximately 47.5 ± 3.3 pmol/min/mg protein versus 423.3 ± 44.4 pmol/min/mg for MPH — approximately a 10-fold difference [Ref 1, web-retrieved from Grokipedia citing Markowitz 2013].
**Consequences:**
1. **Sustained action:** Slower enzymatic breakdown → prolonged duration of effect compared to MPH's 2–3 hour half-life [Ref 1]
2. **Reduced ethanol interaction:** MPH undergoes CES1-mediated transesterification with ethanol to form ethylphenidate, potentiating euphoria and abuse liability. IPH's CES1 resistance substantially reduces this ethanol interaction [Ref 1, Ref 9]. **This is a critical safety distinction from MPH.**
### Metabolism and Metabolites
Manier et al. (2020 [Ref 2]) identified 17 metabolites of IPH in rat urine using UHPLC-HRMS/MS: 14 phase I and 3 phase II metabolites. Human S9 fraction experiments confirmed that primary hydrolysis to the corresponding carboxy metabolite (ritalinic acid analog) is the dominant pathway. Carboxy metabolites are recommended as additional analytical targets alongside the parent compound for toxicological screening [Ref 2].
The primary metabolite is ritalinic acid (via ester hydrolysis). Phase I oxidative metabolism (hydroxylation) and phase II conjugation (glucuronidation) also occur [Ref 2].
**CYP enzyme involvement:** No IPH-specific CYP data published. By analogy with ethylphenidate (the closest well-studied analog), CYP2C19 is likely the most active isoform, with contributions from CYP1A2, CYP2B6, CYP2C9, CYP2D6, and CYP3A4 [Ref 14]. **FLAG: This is structural analog inference; no IPH-specific CYP data published.**
### Pharmacokinetics
**No human pharmacokinetic studies for IPH have been published.** This is a critical data gap.
In rats (Markowitz et al. 2013 [Ref 1]), intraperitoneal administration of IPH at 10 mg/kg produced:
- Locomotor stimulation onset within ~10 minutes
- Sustained elevation over 120 minutes (vs MPH's shorter-duration profile)
- Prolonged duration consistent with CES1 resistance
**Half-life:** Not established in humans. The seed data lists 5 days as a "tolerance half-life" (not a pharmacokinetic half-life). No published human PK data supports a specific half-life estimate. **FLAG: The "5 days" figure in the seed data refers to tolerance half-life, not pharmacokinetic half-life, and lacks a published primary source.**
**Bioavailability:** No published data. By analogy with MPH (oral bioavailability ~30% for d-MPH due to CES1 presystemic metabolism), IPH's bioavailability may be higher due to CES1 resistance, but this is unconfirmed [Ref 9]. **FLAG: Speculation — no human PK data.**
---
## History
### Discovery and Original Synthesis
Isopropylphenidate was first reported in the scientific literature in **1961**, predating its pharmacological characterization by over 50 years. The compound was studied as part of systematic synthetic chemistry programs exploring methylphenidate ester analogs [web-retrieved, historical reference; original 1961 paper not directly verified].
A **US patent** was filed by Markowitz (University of South Carolina) and colleagues around **2010–2011**, proposing IPH for treatment of ADHD and fatigue-related disorders [Ref 18]. This established the therapeutic rationale for the isopropyl ester modification.
### Primary Pharmacological Characterization
**Markowitz, Zhu, and Patrick (2013 [Ref 1])** published the foundational pharmacological characterization in the *Journal of Child and Adolescent Psychopharmacology*. This study:
- Confirmed synthesis of dl-IPH via esterification of ritalinic acid
- Characterized in vitro DAT/NET selectivity
- Demonstrated 10-fold CES1 resistance vs MPH
- Showed reduced ethanol interaction liability
- Provided in vivo locomotor data in rats
- Proposed IPH "warranting further study and development as a novel psychotherapeutic agent"
### Research Chemical Market Emergence
IPH appeared on online research chemical markets in **2013–2014**, following publication of the Markowitz et al. paper and simultaneous escalation in regulation of ethylphenidate. By **2015**, it was established in the UK's NPS market, partly as an alternative to then-regulated EPH [web-retrieved; Carlier et al. 2019 [Ref 4]; Luethi/Liechti 2020 [Ref 5]].
### Regulatory History
- **April 10, 2015:** UK Temporary Class Drug Order (TCDO) applied to IPH and related methylphenidate-based NPS by the ACMD [Ref 15, Ref 17]
- **November 26, 2016:** Germany controls IPH under the New Psychoactive Substances Act (NpSG) [Ref 27]
- **February 2016:** Canada notifies stakeholders of proposed Schedule III amendments [Ref 26]
- **May 31, 2017:** UK permanent Class B scheduling under Misuse of Drugs Act 1971 [Ref 16]
- **2017:** Canada Schedule III CDSA finalized [Ref 26]
---
## Subjective Effects
**No controlled human studies of IPH's subjective effects have been published.** All available human evidence is from user self-reports.
### From User Reports (user-report-only data; not controlled)
Community sources (Erowid, PsychonautWiki, Reddit) describe IPH's subjective profile as closely resembling MPH but with a smoother onset and extended plateau. Reported qualities include:
**Cognitive/Thinking:**
- Focus enhancement and motivation enhancement (most commonly reported)
- Thought acceleration at higher doses
- Reduced cognitive fatigue during sustained tasks
- Cognitive euphoria at moderate doses, typically described as milder than amphetamines
**Physical:**
- Stimulation (energy, wakefulness)
- Appetite suppression
- Mild vasoconstriction and dry mouth
- At higher doses: bruxism, excessive sweating, tachycardia
- Compulsive redosing urge described in user reports, especially with insufflation
**Affective:**
- Mild mood enhancement (less pronounced than MDMA or amphetamines)
- Post-effect irritability and mood depression at higher doses / next day
- Anxiety at higher doses
**Duration Characteristics (user-report-only):**
The seed database dose/duration data (oral total 3.5–6 hours; insufflated total 2.5–4 hours) is consistent with published in vivo rodent data showing IPH has sustained stimulant effects beyond MPH's typical duration [Ref 1] and consistent with published user consensus [web-retrieved].
**Note:** All subjective effect data is user-report-only. No randomized controlled trials or human pharmacodynamic studies have been published. User reports are consistent with the known DAT>NET selectivity (dopaminergic stimulation more prominent than noradrenergic) and with IPH's extended duration from CES1 resistance.
---
## Safety & Toxicity
### LD50 and Toxic Dose
**No LD50 data for IPH has been published in any species.** The exact toxic dosage is unknown. This is a critical gap [Ref 1, Ref 3; confirmed by web-retrieved sources].
### Overdose Profile (Structural Analog Inference)
Given IPH's mechanism as a DAT/NET reuptake inhibitor, overdose toxicology can be expected to parallel MPH overdose, which presents with (Spiller et al. 2013 [Ref 19]):
- Mydriasis, tremor, agitation, hyperreflexia
- Combative behavior, confusion, hallucinations, delirium, anxiety, paranoia
- Movement disorders, seizures
- Cardiovascular: tachycardia, hypertension
- Severe complications: hyperthermia, rhabdomyolysis, cardiac arrhythmia
- Management: benzodiazepines first-line; antipsychotics (ziprasidone, haloperidol) for refractory agitation
**FLAG:** This is structural analog inference. No IPH-specific overdose case reports exist in the published literature. Emergency clinicians should treat IPH presentations as MPH-class stimulant toxicity.
### Published Case Reports / Fatalities
**No fatalities or case reports of IPH overdose have been published in the scientific literature.** As of available literature (most recent: web-retrieved sources noting no fatalities discussed as of ~2017), IPH has produced no documented deaths.
By contrast, the closely related ethylphenidate (EPH) has been associated with 7 fatalities (Maskell et al. 2016 [Ref 13]), illustrating that phenidate class analogs carry real toxicity risk.
### Cardiovascular Risks
As a sympathomimetic stimulant (DAT/NET inhibitor), IPH predictably causes:
- Increased heart rate and blood pressure
- Risk of cardiac arrhythmia at high doses
- Brugada phenotype risk — by analogy with methylphenidate, which can induce this at supratherapeutic doses [Ref from search: Raja et al. 2026 on cardiovascular adverse effects of psychiatric medications]
**FLAG:** No IPH-specific cardiovascular data published. All cardiovascular risk assessment is by structural analog inference from MPH.
### Psychological Risks
User reports and class-level evidence indicate:
- Risk of stimulant psychosis with high-dose or chronic use (paranoia, hallucinations)
- Compulsive redosing pattern particularly with insufflation
- Post-effect dysphoria and depression ("comedown")
- Insomnia
No IPH-specific psychological adverse event studies exist.
### Organ Toxicity
No published data on hepatotoxicity, nephrotoxicity, or neurotoxicity specific to IPH.
---
## Harm Reduction
### Risk Reduction Strategies
Based on class-level evidence for monoaminergic stimulants:
1. **Dose control:** Start with lowest effective dose; avoid escalation. Oral route is safer than insufflation due to reduced compulsive redosing.
2. **Avoid concurrent stimulant use:** Combining with other stimulants (including caffeine) compounds cardiovascular strain.
3. **Avoid MDMA combination:** The MPH+MDMA human study (Hysek et al. 2014 [Ref 20]) demonstrated significantly amplified cardiovascular adverse effects with no enhancement of desired effects — directly applicable to IPH.
4. **Avoid tramadol:** Tramadol inhibits both serotonin and norepinephrine reuptake and lowers seizure threshold; combining with an NE-active stimulant greatly amplifies both risks (Sansone & Sansone 2009 [Ref 21]; Hassamal et al. 2018 [Ref 22]).
5. **Alcohol:** Unlike MPH, IPH's CES1 resistance substantially reduces formation of a transesterification product (as occurs with MPH+ethanol → ethylphenidate). However, cardiovascular interaction and CNS effects of combined alcohol+stimulant remain a concern [Ref 1, Ref 9].
6. **Contraindications:** Cardiovascular disease, hypertension, arrhythmias, anxiety disorders, psychosis, seizure disorders.
7. **Testing:** No published colorimetric reagent test data specific to IPH. The thermal instability of phenidate analogs under GC-MS conditions (decomposition in injection port) is noted [Ref 7]; LC-MS/MS is the preferred analytical method.
### Emergency Response
In suspected IPH overdose, management should follow MPH/stimulant overdose protocol [Ref 19]:
- Benzodiazepines for agitation/seizures
- Supportive cardiovascular management
- Temperature monitoring
- Contact poison control
---
## Tolerance & Dependence
### Tolerance Development
**No IPH-specific tolerance data from human or animal studies exist.** Tolerance inference is from the MPH class.
Chronic MPH administration produces tolerance to locomotor effects (not sensitization, which distinguishes it from amphetamines) (McNamara et al. 1993 [Ref 24]). This is consistent with the seed database's description of "develops with prolonged and repeated use."
The seed data claims:
- Tolerance half-life: 5 days
- Full reset: 1.5 weeks
- Cross-tolerances: dopamine, stimulant
**FLAG: No published primary source supports the specific "5 days / 1.5 weeks" tolerance timeline for IPH. This appears to be community-derived consensus, not published experimental data. Needs editorial review.**
The cross-tolerance with other dopaminergic stimulants is pharmacologically plausible (shared DAT mechanism) but has not been specifically characterized for IPH.
### Dependence Liability
**No controlled dependence studies for IPH exist.** Class-level assessment:
As a DAT reuptake inhibitor, IPH has abuse liability. User community reports suggest psychological dependence tied to productivity use (ADHD self-medication context), with compulsive redosing urge being a notable feature. Rated as "moderately addictive with a high potential for abuse" in community consensus (seed database) — pharmacologically plausible given DAT inhibition, but no formal study.
Importantly, IPH's **slower CES1 metabolism and lower NET activity** may confer somewhat reduced abuse liability compared to MPH (by reducing the rapid rise/fall cycle that drives reinforcement) and compared to EPH (which has more extreme DAT selectivity). This is speculative inference only [Ref 1, Ref 12].
### Withdrawal
No published data. By class inference: stimulant withdrawal (fatigue, hypersomnia, depression, anhedonia) expected with abrupt cessation after chronic use. No severe physical withdrawal reported in user community [web-retrieved].
---
## Interactions
### Tramadol — Flagged as LETHAL (seed data)
**Mechanism:** Tramadol inhibits serotonin AND norepinephrine reuptake (SNRI-like action) in addition to opioid receptor activity, and significantly lowers seizure threshold. Combining with a stimulant that inhibits NET (IPH) compounds noradrenergic effects and further increases seizure risk. Serotonin syndrome risk is also elevated [Ref 21, Ref 22].
**Assessment:** The "lethal" designation in seed data is plausible given the compounded seizure and cardiovascular risks, but **no IPH+tramadol case report or study exists**. The interaction is pharmacologically well-characterized for tramadol+serotonergic/adrenergic drugs generally. **FLAG: Severity not confirmed by published IPH-specific data; based on tramadol pharmacology and class extrapolation.**
### MDMA — Flagged as DANGEROUS (seed data)
**Mechanism:** MDMA is a serotonin, dopamine, and norepinephrine releaser. Hysek et al. (2014 [Ref 20]) conducted a human RCT demonstrating that MPH (0.5 mg/kg) + MDMA (125 mg) produced significantly elevated cardiovascular adverse effects (heart rate, blood pressure) compared to either drug alone, without enhanced subjective effects.
**Assessment:** This human evidence directly informs IPH's expected interaction with MDMA. IPH's more selective DAT profile may reduce serotonergic component of the interaction compared to MPH, but the cardiovascular amplification is the primary concern. **FLAG: Severity extrapolated from MPH data; no IPH+MDMA-specific study exists.**
### Alcohol — Listed as UNKNOWN (seed data)
**Assessment:** IPH's 10-fold CES1 resistance substantially reduces the transesterification pathway (MPH+EtOH → EPH) that represents a pharmacokinetic drug interaction for MPH. However, pharmacodynamic interactions (combined cardiovascular strain, CNS effects) remain relevant. The "unknown" classification in the seed database is appropriate given the absence of IPH+alcohol-specific data [Ref 1, Ref 9].
### MAOIs
Not mentioned in seed data, but this is a standard critical contraindication for all monoaminergic stimulants. Combining a DAT/NET inhibitor with an MAOI can cause hypertensive crisis and/or serotonin syndrome. **FLAG: Standard class contraindication; no IPH-specific data.**
---
## Legal Status
| Jurisdiction | Status | Effective Date | Notes |
|---|---|---|---|
| **United Kingdom** | Class B, Misuse of Drugs Act 1971 | May 31, 2017 (permanent); TCDO April 10, 2015 (temporary) | Possession, supply, and production are criminal offenses [Ref 15, Ref 16, Ref 17] |
| **United States** | Not federally scheduled | — | Potentially prosecutable under Federal Analogue Act (21 U.S.C. § 813) as an analog of MPH (Schedule II); state laws vary |
| **Germany** | Controlled under NpSG (New Psychoactive Substances Act) | November 26, 2016 | Production, import for market, and trading prohibited [Ref 27] |
| **Canada** | Schedule III, Controlled Drugs and Substances Act | 2017 (finalized) | Proposed via Canada Gazette February 2016 [Ref 26] |
| **Sweden** | Classified as hazardous substance | — | Specific scheduling date not confirmed [web-retrieved] |
| **Australia** | Uncontrolled at federal level | — | Not listed in Therapeutic Goods Act schedules as of available data [web-retrieved]; confirm via TGA |
| **International** | Not scheduled under UN drug conventions | — | Not listed in 1961/1971/1988 treaties |
**FLAG:** Australia status based on 2024 web search summary; direct TGA/Poisons Standard verification not completed. Sweden "hazardous substance" designation needs specific legislative citation.
---
## Clinical Trials
**No clinical trials for isopropylphenidate have been registered on ClinicalTrials.gov.** A search returned zero results [clinical trial search, step 4].
The 2013 Markowitz paper proposed IPH as "warranting further study and development as a novel psychotherapeutic agent" [Ref 1], and a US patent was filed for ADHD and fatigue indications [Ref 18], but no Phase I or Phase II trials have been initiated.
---
## Community Feedback Analysis
**No community feedback submitted** in Part A2 of the brief.
---
## Gaps & Flags
### Critical Safety-Critical Flags
1. **⚠️ No LD50 or toxic dose data:** Exact toxic dosage is unknown for any species. Any dose range in the article must be flagged as unverified against lethality data.
2. **⚠️ Tramadol interaction severity:** Rated "lethal" in seed data but no IPH+tramadol case report exists. Based on tramadol pharmacology (SNRI + seizure threshold lowering). **Severity designation needs editorial review.**
3. **⚠️ MDMA interaction severity:** Rated "dangerous" — supported by MPH+MDMA human RCT (Hysek 2014 [Ref 20]). IPH extrapolation is pharmacologically sound but not directly confirmed.
4. **⚠️ Tolerance timeline (5 days / 1.5 weeks):** No published primary source. Community consensus only.
### Data Not Verified Against Published Sources
5. **No human pharmacokinetic data:** Half-life, Tmax, bioavailability, Cmax — all uncharacterized in humans. Duration data in seed database is based on user reports only.
6. **Binding affinity values (Ki/IC50):** The specific numeric values (DAT IC₅₀ ~200 nM, NET >10,000 nM) were obtained via secondary web aggregation from Grokipedia citing Markowitz 2013. Full-text access to Markowitz 2013 required for direct verification.
7. **CYP enzyme involvement:** No IPH-specific CYP data. Inferred from ethylphenidate analog [Ref 14].
### Sections Relying on Structural Analog Inference
8. **Overdose toxicology:** Extrapolated from MPH overdose data [Ref 19].
9. **Cardiovascular adverse effects:** Extrapolated from MPH/phenidate class.
10. **Withdrawal profile:** Extrapolated from stimulant class.
11. **Bioavailability estimate:** IPH's CES1 resistance may increase oral bioavailability beyond MPH's ~30%, but unconfirmed.
### Other Gaps
12. **No published case reports or fatalities specific to IPH.** (Ethylphenidate fatalities exist [Ref 13] as comparative reference.)
13. **Australia scheduling:** Reported as uncontrolled but TGA Poisons Standard direct search not completed.
14. **Sweden specific law:** "Hazardous substance" designation cited from web sources without specific legislation name/date.
15. **Isomeric SMILES not confirmed:** The provided SMILES (CC(C)OC(=O)C(C1CCCCN1)C2=CC=CC=C2) is canonical (racemic); the active threo diastereomers are d-IPH and l-IPH but their isomeric SMILES are not provided here.
16. **First synthesis date:** 1961 claimed in web sources; original 1961 paper not directly verified via API tools.
17. **Reagent test colors:** No published colorimetric reagent test (Marquis, Mandelin, etc.) data specific to IPH found.