Dextroamphetamine

# Research Output: Dextroamphetamine

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## Chemical Identity

**Verified from PubChem CID 5826** [Ref 20]:

| Field | Value |
|---|---|
| PubChem CID | 5826 |
| IUPAC name | (2S)-1-phenylpropan-2-amine |
| Molecular formula | C₉H₁₃N |
| Molecular weight | 135.21 g/mol |
| InChIKey | KWTSXDURSIMDCE-QMMMGPOBSA-N |
| Isomeric SMILES | C[C@@H](Cc1ccccc1)N |
| CAS number (free base) | 51-64-9 |
| CAS number (sulfate salt) | 51-63-8 |
| Systematic name | (2S)-1-phenylpropan-2-amine |

**Discrepancies with brief seed data:** The brief had all chemical identity fields (SMILES, molecular formula, molecular weight, InChIKey, PubChem CID) empty. All values are now confirmed from PubChem. The IUPAC name in the brief ((2S)-1-phenylpropan-2-amine) is correct.

**Stereochemistry:** Dextroamphetamine is the (2S)- or (+)-enantiomer of amphetamine, also referred to as d-amphetamine. The S-configuration at the chiral center (carbon-2) confers the dextrorotatory optical activity. The d-enantiomer is approximately 3–5× more potent than the l-enantiomer (levoamphetamine) for CNS stimulant effects, owing to greater relative affinity at dopamine and norepinephrine targets [Ref 21]. Adderall, a widely prescribed mixed amphetamine salt formulation, contains a 75:25 d:l ratio.

**Physical properties:** The free base is a colourless to pale yellow volatile oil; the sulfate salt is a white crystalline powder. Melting point of the sulfate salt: 300°C (decomposition). The compound is highly water-soluble as the salt form and somewhat lipid-soluble as the free base. No published melting point for the free base was located in primary sources.

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## Pharmacology

### Mechanism of Action

Dextroamphetamine exerts its primary pharmacological effects through three inter-related mechanisms at monoamine synapses [Ref 1, Ref 5, Ref 24]:

**1. Substrate-type releasing agent (reverse transport):** d-Amphetamine is a substrate for the dopamine transporter (DAT), norepinephrine transporter (NET), and serotonin transporter (SERT). It enters presynaptic neurons via these transporters and acts as a "substrate" or releasing agent, causing monoamine efflux through carrier-mediated reverse transport — a process mechanistically distinct from reuptake inhibition [Ref 1, Ref 4]. This reverse transport at DAT and NET accounts for the primary stimulant and reinforcing effects.

**2. VMAT2 redistribution:** Once intracellular, d-amphetamine disrupts vesicular monoamine transporter-2 (VMAT2) function, causing redistribution of dopamine (and to a lesser extent norepinephrine and serotonin) from synaptic vesicles into the cytoplasm [Ref 10, Ref 13]. This cytoplasmic pool is then effluxed outward via reverse transport at the plasma membrane transporter. A 2024 cryo-EM study of human VMAT1 confirmed that amphetamine shares the same substrate binding pocket as dopamine and other monoamines [Ref 10]. The efflux process requires concerted action at both VMAT2 and DAT and does not require cytosolic Ca²⁺ [Ref 13].

**3. TAAR1 agonism:** Dextroamphetamine acts as an agonist at trace amine-associated receptor 1 (TAAR1), an intracellular Gs-protein-coupled receptor [Ref 22, Ref 23, Ref 34]. TAAR1 activation by intracellular amphetamine triggers downstream signaling cascades including RhoA and CaMKII pathways that induce transporter internalization (endocytosis of DAT and NET), further reducing reuptake capacity and amplifying monoamine efflux [Ref 23]. TAAR1 also activates phosphorylation-dependent mechanisms that regulate transporter surface expression [Ref 22].

**Additional mechanisms:**
- Alpha- and beta-adrenergic receptor stimulation (via increased synaptic norepinephrine) [Ref 21]
- Weak inhibition of monoamine oxidase (MAO) at high concentrations [Ref 21]
- Inhibition of vesicular storage (VMAT2 depletion) [Ref 11]

### Receptor Binding Affinities

Data from Han & Gu (2006) using human transporter-transfected HEK cells [Ref 16]:

| Transporter | Ki (μM) | Selectivity |
|---|---|---|
| hNET | 0.07–0.10 | Highest affinity |
| hDAT | ~0.60 | 5–9× less potent than NET |
| hSERT | 20–40 | 200–500× less potent than NET |

**Key interpretation:** Dextroamphetamine has substantially higher affinity for NET than DAT, making it more potent at releasing norepinephrine than dopamine. SERT affinity is very low, making its serotonergic actions far weaker than its catecholaminergic actions. This binding profile distinguishes amphetamine from MDMA (which has high SERT affinity) and from cocaine (which inhibits all three transporters approximately equally) [Ref 16].

Rothman & Baumann (2006) characterize d-amphetamine as a "DA-preferential releasing agent" — meaning its reinforcing and abuse-related properties are more tied to DAT/dopamine than to SERT/serotonin [Ref 24]. The high NET affinity also explains its utility for ADHD (prefrontal cortex noradrenergic enhancement) and narcolepsy (noradrenergic wakefulness promotion).

**TAAR1:** Dextroamphetamine acts as an agonist at human TAAR1, with potency in the low micromolar range (specific Ki not extracted from primary sources); structural studies confirm a consensus binding motif in the TAAR1 orthosteric pocket [Ref 22, Ref 34].

### Pharmacokinetics

Data primarily from FDA prescribing information (Dexedrine) and StatPearls clinical synthesis [Ref 20, Ref 21]:

| Parameter | d-Amphetamine (oral) | Notes |
|---|---|---|
| Oral bioavailability | ~90% | Well absorbed from GI tract |
| Protein binding | <20% | Moderate |
| Volume of distribution | ~4 L/kg | Widely distributed; CNS-penetrant |
| Tmax (immediate-release) | ~3 hours | After 15 mg oral; 3 × 5 mg tablets |
| Cmax (15 mg oral) | ~36.6 ng/mL | After 3 × 5 mg tablets |
| Elimination half-life | 9–11 hours (adults) | At normal urine pH |
| Food effect | Delays Tmax by ~2.5 h | Does not affect total absorption (AUC) |

**Metabolism:** Primarily hepatic via CYP2D6 (hydroxylation to 4-hydroxyamphetamine and norephedrine — an active metabolite); also metabolized by CYP1A2, CYP3A4, and monoamine oxidase [Ref 21]. Genetic CYP2D6 polymorphism is clinically relevant: poor metabolizers may have higher plasma exposures; CYP2D6 inhibitors (fluoxetine, paroxetine, bupropion) can elevate d-amphetamine levels.

**Elimination:** Approximately 30–40% of a dose is excreted as unchanged amphetamine in urine. pH-dependent: alkaline urine (e.g., with sodium bicarbonate) markedly decreases renal clearance and prolongs half-life; acidic urine (e.g., vitamin C/ascorbic acid) accelerates elimination. This pH dependence is clinically significant for both overdose management and for drug interactions.

**Children vs adults:** Elimination half-life is approximately 1 hour shorter in children than adults.

**Insufflated route:** Pharmacokinetic studies of intranasal administration of lisdexamfetamine-derived d-amphetamine show onset within 1–5 minutes and Tmax substantially shorter than oral [Ref 33]. No controlled human PK studies of insufflated pure dextroamphetamine were found in the literature search; the brief's duration data for insufflated route is consistent with expected pharmacokinetics given the shorter Tmax.

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## History

**First synthesis (1887):** Amphetamine (phenylisopropylamine) was first synthesized in Germany by Romanian chemist Lazăr Edeleanu, who named it phenylisopropylamine. No pharmacological activity was recognized at the time [Ref 31].

**Pharmacological discovery (1927):** Gordon Alles, an American pharmacologist, independently resynthesized amphetamine while searching for an ephedrine substitute. He tested it on himself and characterized its sympathomimetic and CNS stimulant properties. Alles filed a US patent for amphetamine sulfate and hydrochloride in 1932, recognizing him as the discoverer of their medicinal value [Ref 31].

**Commercial introduction (1934):** Smith, Kline & French began marketing amphetamine inhalers under the brand name Benzedrine for nasal congestion. Within a decade, oral tablets were introduced for narcolepsy and depression.

**Dextroamphetamine isolation and clinical use:** The dextro-isomer was recognized as more potent than the racemate, and Dexedrine (dextroamphetamine sulfate) was developed as a more selective formulation. Dexedrine was approved by the FDA and became a widely prescribed medication for ADHD and narcolepsy.

**World War II (1939–1945):** Benzedrine (amphetamine sulfate) was officially approved for use by the Royal Air Force in November 1942, reversing a prohibition policy in place since September 1939. An estimated 72 million amphetamine tablets were distributed to British armed forces during WWII. Dosing protocols recommended 5–10 mg every 5–6 hours for alertness maintenance, not exceeding 20 mg/day [Ref 37]. Allied and Axis forces both employed amphetamines extensively for combating fatigue in combat operations.

**Post-war regulatory history:** Following widespread misuse in the 1950s–1970s (including non-prescription "diet pills" and stimulant abuse), amphetamines were placed under increasing regulatory control. The US Controlled Substances Act (1970) classified dextroamphetamine as Schedule II. The UK Misuse of Drugs Act (1971) classified amphetamines as Class B (Schedule 2). Dexedrine (dextroamphetamine sulfate) remains FDA-approved for ADHD and narcolepsy as of 2026.

**Brand names:** Dexedrine (US, Canada, UK), Dextrostat (US), Attentin (Spain), Procentra (oral solution, US). As of 2026, lisdexamfetamine (Vyvanse, a prodrug of d-amphetamine) is more widely prescribed than Dexedrine in many markets.

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## Subjective Effects

Data from controlled human laboratory studies:

**CNS stimulation:** At oral doses of 10–20 mg in healthy volunteers, d-amphetamine produces significant increases in ratings of Elation, Vigor, Stimulation, and Euphoria relative to placebo [Ref 26, Ref 17]. The magnitude of euphoria shows substantial inter-individual variation partly attributable to DAT gene (SLC6A3) polymorphisms — individuals with the C/C genotype at rs460000 reported approximately 2× higher euphoria and stimulation ratings at both 10 and 20 mg compared with other genotypes [Ref 17].

**Cognitive effects:** Improved performance on psychomotor tasks (Digit Symbol Substitution Task), improved attention, reaction time, and working memory in both ADHD and healthy populations [Ref 17, Ref 7]. The Cortese 2018 network meta-analysis found amphetamines to have the largest effect sizes for ADHD symptom reduction compared with other pharmacological interventions [Ref 35].

**Cardiovascular:** Dose-dependent increases in systolic and diastolic blood pressure and heart rate [Ref 12, Ref 17]. The Cochrane review by Chan et al. (2025) confirms amphetamines have potential to increase blood pressure with chronic daily use, though the long-term risk-benefit balance remains uncertain [Ref 12].

**Appetite suppression:** Significant anorexigenic effects; mechanism involves both direct hypothalamic effects and melanocortin system activation (MC4R pathway) [Ref 14].

**Duration (oral, immediate-release):** Based on PK data and clinical reports — onset 15–30 minutes, peak effects 2–4 hours, total duration 4–6 hours (short-acting) or 8–12 hours (extended-release) [Ref 21, Ref 28]. Seed data duration values in the brief are consistent with published PK and clinical data.

**Insufflated route:** Onset reported within 1–5 minutes, peak 1–2 hours, duration 3–6 hours, consistent with faster Tmax from intranasal absorption bypassing first-pass metabolism. No formal controlled study of pure insufflated dextroamphetamine duration found; lisdexamfetamine intranasal PK data suggests comparable d-amphetamine systemic exposure [Ref 33].

**Sleep disruption:** Amphetamines suppress REM sleep and reduce total sleep time. Insomnia is one of the most common adverse effects reported in clinical trials.

**Peripheral sympathomimetic effects documented in controlled studies:** Increased blood pressure (systolic and diastolic), tachycardia, decreased appetite, dry mouth, diaphoresis [Ref 21, Ref 28].

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## Safety & Toxicity

### Acute Toxicity

**Human lethal dose range:** Acute toxicity data indicate death has occurred at doses of 20–25 mg/kg in sensitive individuals; however, chronic abusers may develop tolerance to doses far exceeding this — tolerance to as high as 15,000 mg/day has been reported in case literature (though such extreme reports warrant caution) [Ref 21].

**LD50 (animal):** No specific LD50 data for d-amphetamine in humans is established. Animal data (rats): approximately 55 mg/kg oral. The therapeutic dose range in humans (5–60 mg/day) is far below reported toxic doses, though the therapeutic index is narrow in sensitive individuals.

**Overdose signs and symptoms:** Hyperactivity, agitation, hyperthermia, tachycardia, hypertension, mydriasis, tremors, seizures, altered mental status, rhabdomyolysis, cerebrovascular accident [Ref 21].

**Overdose management:** No specific antidote. Treatment is supportive: activated charcoal (if recent ingestion), benzodiazepines (agitation/seizures), antihypertensives (nitroprusside for severe hypertension), cooling measures for hyperthermia, cardiac monitoring [Ref 21].

### Chronic Toxicity

**Cardiovascular:** Long-term daily use is associated with elevated blood pressure. The Cochrane systematic review (Chan et al. 2025) identified significant evidence that amphetamines raise blood pressure, though the long-term cardiovascular outcome data remain limited [Ref 12]. Cardiomyopathy, myocardial infarction, and cerebrovascular accident are documented rare adverse events [Ref 21].

**Sudden cardiac death:** FDA black box warning for stimulants notes risk of sudden cardiac death in patients with structural cardiac abnormalities. This risk applies to both prescribed therapeutic doses and misuse [Ref 21].

**High-dose neurotoxicity:** D-amphetamine at high doses causes microglial activation in the striatum and dopaminergic nerve terminal damage, mediated by reactive oxygen species (ROS) and reactive nitrogen species (RNS) [Ref 18, Ref 40]. This is pharmacologically distinct from low-dose therapeutic use — Thomas et al. (2004) confirmed that d-amphetamine (at high doses) causes microglial activation as a marker of striatal neurotoxicity, similar to methamphetamine and MDMA but not seen with non-neurotoxic amphetamine-class compounds [Ref 18].

**Amphetamine psychosis:** Chronic high-dose use can produce a paranoid psychotic state clinically indistinguishable from paranoid schizophrenia. Robinson & Becker (1986) describe progressive behavioral sensitization with repeated amphetamine administration as an animal model of amphetamine psychosis [Ref 2]. The dopamine hypothesis of schizophrenia is partly derived from observations of amphetamine psychosis.

**Pregnancy:** Associated with increased risk of premature delivery, low birth weight, gastroschisis, and preeclampsia [Ref 21]. Amphetamines are excreted in breast milk at levels 3–7× higher than maternal plasma — breastfeeding is contraindicated [Ref 21].

**Growth suppression in children:** Long-term stimulant use in pediatric populations is associated with reduced weight and height velocity; clinical significance remains debated [Ref 28].

**Psychological risks:** Anxiety exacerbation, depressive "crashes" after acute use, mania induction in predisposed individuals, paranoia and psychosis with chronic high-dose use [Ref 21, Ref 28].

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## Harm Reduction

**Published risk reduction strategies:**

1. **Titrate dosing:** Begin at the lowest effective dose; therapeutic oral doses for ADHD start at 2.5–5 mg. Therapeutic window should be respected [Ref 21].
2. **Monitor blood pressure and heart rate:** Cardiovascular screening is indicated before starting and during treatment [Ref 12].
3. **Avoid in cardiac disease:** Contraindicated in advanced arteriosclerosis, symptomatic cardiovascular disease, and structural heart defects [Ref 21].
4. **MAOI washout:** At least 14-day washout from MAOIs before initiating; co-administration is contraindicated due to hypertensive crisis risk [Ref 21].
5. **pH considerations:** Ascorbic acid/vitamin C co-administration can reduce amphetamine efficacy and blood levels (acidifies urine, accelerates excretion). Conversely, antacids and sodium bicarbonate can potentiate and prolong effects [Ref 21].
6. **Avoid combination with other stimulants:** Including cocaine, caffeine at high doses; additive cardiovascular stress [Ref 28].
7. **Harm reduction for insufflated route:** Use sterile equipment; avoid sharing; rinse nasal passages after use. Route change to oral significantly reduces cardiovascular peak loading [Ref 28].
8. **Identify and avoid interaction risks:** MAOIs, CYP2D6 inhibitors, serotonergic drugs (risk of serotonin syndrome), acidifying agents [Ref 21].
9. **Testing:** Reagent tests (Marquis reagent turns orange-to-brown for amphetamine; Mecke turns yellow-green) can confirm identity and detect adulterants. Fentanyl test strips are recommended given the adulterant crisis.

**Contraindications from literature** [Ref 21]:
- Hypersensitivity to amphetamine or any component
- History of or current MAOI use within 14 days
- Advanced arteriosclerosis, symptomatic cardiovascular disease
- Moderate-to-severe hypertension
- Hyperthyroidism
- Glaucoma
- Agitated states
- History of drug abuse (relative)
- Pregnancy (relative)

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## Tolerance & Dependence

### Tolerance

Tolerance to the subjective and cardiovascular effects of amphetamines develops with repeated use via multiple mechanisms [Ref 2, Ref 11]:

1. **Dopamine receptor downregulation:** Chronic amphetamine exposure downregulates D2 dopamine autoreceptors, blunting the presynaptic feedback inhibition that would normally limit DA release.
2. **Transporter expression changes:** Chronic exposure alters DAT and VMAT2 expression; VMAT2 redistribution affects the cytoplasmic vs vesicular dopamine pool dynamics.
3. **Depletion of monoamine stores:** High-frequency use depletes synaptic monoamine stores faster than synthesis can replenish them.

Tolerance develops differentially — tolerance to anorectic effects often precedes tolerance to mood/stimulant effects. Cross-tolerance exists with other catecholamine-releasing agents.

### Behavioral Sensitization

With interrupted or intermittent dosing patterns, some users instead develop behavioral sensitization (the opposite of tolerance) — progressive enhancement of stimulant-induced locomotion and reinforcing effects. Robinson & Becker (1986) characterize this as involving persistent changes in DA release that may underlie some aspects of amphetamine addiction [Ref 2]. Sensitization is mediated partly through VMAT2 redistribution [Ref 11].

### Dependence

Dextroamphetamine is Schedule II (US) due to high abuse potential and capacity to produce severe psychological dependence. Physical dependence (physiological withdrawal) is also documented but generally less severe than with CNS depressants [Ref 21].

**Withdrawal syndrome:** Following cessation after chronic use: marked fatigue and hypersomnia (rebound from sleep suppression), depressed mood, anhedonia, increased appetite, dysphoria, and irritability lasting days to weeks. This reflects the depletion of monoamine stores and receptor adaptations [Ref 28].

**DSM-5 Stimulant Use Disorder** criteria apply, requiring ≥2 of 11 criteria within a 12-month period. Data on amphetamine-type stimulant use disorder prevalence is reviewed in a forthcoming COMPASS meta-analysis protocol (Bissonnette et al. 2026) [Ref — see PMID 41656281, not included in registry as protocol only].

**Non-medical use:** McCabe et al. (2005) found 6.9% lifetime prevalence of non-medical prescription stimulant use (including Dexedrine) among US college students, with higher rates in fraternities/sororities and competitive universities [Ref 8].

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## Interactions

### High-Severity Interactions (Contraindicated or Potentially Fatal)

**MAOIs (contraindicated):** Co-administration of dextroamphetamine with monoamine oxidase inhibitors (phenelzine, tranylcypromine, selegiline, linezolid, methylene blue) is contraindicated. The combination can cause severe hypertensive crisis — massive norepinephrine accumulation leads to life-threatening blood pressure elevation — as well as serotonin syndrome. A 14-day MAOI washout is required before initiating [Ref 21].

**Tramadol ("lethal" in brief):** Tramadol is a dual serotonin/norepinephrine reuptake inhibitor plus mu-opioid agonist. Dextroamphetamine's serotonin-releasing activity combined with tramadol's SERT inhibition could theoretically precipitate serotonin syndrome. Published case reports of fatal serotonin syndrome with tramadol involve co-administration with other serotonergic agents (SSRIs, SNRIs); the specific amphetamine-tramadol combination is described as potentially life-threatening through the same mechanism [Ref — web search; no specific published case report for dextroamphetamine + tramadol found in indexed literature]. **Flag: The interaction severity rating of "lethal" in the brief is not directly confirmed by a published case report specific to dextroamphetamine + tramadol. The mechanism predicts dangerous/potentially life-threatening serotonin syndrome, but "lethal" as an absolute category may overstate certainty. Recommend reclassifying to "dangerous" pending editorial review.**

**PCP ("dangerous" in brief):** Phencyclidine (PCP) acts as an NMDA receptor antagonist with indirect dopaminergic effects. Co-administration with dextroamphetamine, a potent dopamine releaser, could theoretically potentiate psychomimetic effects and place severe cardiovascular and CNS strain. Published literature on the amphetamine+PCP interaction is predominantly animal-based. **Flag: No specific human case report or controlled study for dextroamphetamine + PCP interaction was found in indexed literature. The "dangerous" rating is pharmacologically plausible but not directly evidence-based.**

### Moderate-to-High Severity Interactions

**CYP2D6 inhibitors** (fluoxetine, paroxetine, bupropion): Reduced amphetamine metabolism → elevated plasma levels → increased risk of adverse events including serotonin syndrome [Ref 21].

**Tricyclic antidepressants:** Enhanced cardiovascular and CNS effects of both agents.

**Serotonergic drugs (general):** Elevated serotonin syndrome risk with SSRIs, SNRIs, triptans, linezolid, and St. John's Wort [Ref 21].

**Thiazide diuretics:** Potential to increase amphetamine exposure through alkalinization of urine; listed in FDA label as potentially life-threatening interaction [Ref 20].

**Beta-blockers:** Risk of unopposed alpha-adrenergic stimulation leading to reflex hypertension if beta-blockers are used during amphetamine intoxication (though evidence specifically for dextroamphetamine is limited).

### Lower-Severity / Mechanism-Noted Interactions

**Ascorbic acid (Vitamin C):** Acidifies urine → accelerates amphetamine elimination → reduced efficacy and shorter duration [Ref 21].

**Antacids, sodium bicarbonate:** Alkalinize urine → reduced elimination → prolonged and enhanced effects [Ref 21].

**Cannabis (brief: "unknown"):** No published controlled study on cannabis + dextroamphetamine interaction. Theoretically, cannabis might modulate cardiovascular and anxiogenic effects additively. Not confirmed in indexed literature.

**Alcohol (brief: "unknown"):** Limited specific data. Stimulants can mask perceived intoxication from alcohol, leading to alcohol overconsumption. Adrenergic effects may be additive. ADF Australia notes this interaction [Ref 28].

**Caffeine (brief: "unknown"):** Additive stimulant effects on cardiovascular system expected. No specific dextroamphetamine + caffeine controlled study found.

**GHB/GBL, Ketamine, Methoxetamine, Cocaine (brief: "unknown"):** No published interaction data specific to dextroamphetamine found in indexed literature for these combinations.

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## Legal Status

| Jurisdiction | Status | Schedule/Class |
|---|---|---|
| United States | Controlled substance; legal by prescription | DEA Schedule II (FDA-approved for ADHD and narcolepsy) |
| United Kingdom | Controlled substance; legal by prescription | Class B, Schedule 2 under Misuse of Drugs Act 1971; Class A if prepared for injection |
| Australia | Controlled substance; legal by prescription | Schedule 8 (Controlled Drugs) under Poisons Standard |
| Canada | Controlled substance; legal by prescription | Schedule III under Controlled Drugs and Substances Act (CDSA) |
| European Union | Varies by country; generally requires prescription | Most EU member states classify amphetamines as prescription-only controlled substances |

Sources: DEA scheduling [Ref 21], UK Release [Ref 29], ADF Australia [Ref 28], Canadian CCSA [Ref 30].

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## Clinical Trials

Active and completed trials involving dextroamphetamine from ClinicalTrials.gov search:

| NCT Number | Title | Status | Phase | Condition | Sponsor |
|---|---|---|---|---|---|
| NCT00004556 | The Effects of Dextroamphetamine on Brain Function | Completed | — | Healthy volunteers | NIMH |
| NCT00572767 | Dextro-Amphetamine Added to Physiotherapy in Patients After Stroke | Terminated | Phase 4 | Stroke rehabilitation | Reha Rheinfelden |
| NCT04094025 | Irritation and Sensitization Study of d-Amphetamine Transdermal System | Completed | Phase 1 | Skin tolerability | Noven Therapeutics |
| NCT01711021 | Dextroamphetamine Transdermal System in ADHD (d-ATS) | Completed | Phase 2 | ADHD (children/adolescents) | (Noven) |

Note: Lisdexamfetamine (prodrug of d-amphetamine) has numerous additional completed Phase 3 RCTs for ADHD (adults and children) and binge eating disorder.

The landmark Cortese et al. (2018) Lancet Psychiatry NMA [Ref 35] synthesized 133 RCTs and found amphetamines had the highest efficacy for ADHD symptom reduction in children/adolescents among all pharmacological interventions studied.

**Narcolepsy:** Trotti et al. (2024) conducted the first randomized non-inferiority trial directly comparing modafinil vs amphetamine-dextroamphetamine for narcolepsy type 2 and idiopathic hypersomnia, providing direct comparative effectiveness data [Ref 9].

**Off-label aphasia recovery post-stroke:** Walker-Batson et al. (2001) conducted a double-blind, placebo-controlled trial of dextroamphetamine (paired with speech/language therapy) for aphasia — a Phase 2 trial demonstrating proof of concept for noradrenergic-mediated brain plasticity enhancement in stroke recovery [Ref 19]. NCT00572767 explored stroke rehabilitation with dextroamphetamine but was terminated (completion status unclear).

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## Community Feedback Analysis

No community feedback submitted in the brief's Part A2.

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## Gaps & Flags

### Data Gaps

1. **SMILES/InChIKey/Formula (brief):** These fields were empty in the seed data. All verified from PubChem CID 5826. ✓ Resolved.

2. **Specific binding affinity data for d-amphetamine vs racemate:** The Han & Gu (2006) data [Ref 16] are for amphetamine generally (racemic or unspecified in that context); more specific d-amphetamine enantiomer Ki values were not found in directly retrievable primary sources. The values cited are the best available from a systematic human transporter comparison study. Flag for editorial review if high precision is needed.

3. **No published controlled study of pure insufflated dextroamphetamine PK:** Duration data for insufflated route in the brief is based on the known pharmacokinetic principles and lisdexamfetamine intranasal studies rather than a direct dextroamphetamine insufflation study. This is consistent with expected pharmacokinetics but is inferred, not directly measured for this specific compound and route.

4. **LD50 in humans:** Not established with precision. The "20–25 mg/kg" figure cited in StatPearls is derived from clinical data rather than a formal LD50 study; tolerance markedly confounds acute lethality.

5. **GHB, GBL, Ketamine, Methoxetamine, Cannabis, Cocaine, Caffeine interactions:** No indexed primary research found for dextroamphetamine specifically in these combinations. All listed as "unknown" in the brief — that status is confirmed as accurate.

6. **Amphetamine vs dextroamphetamine neurotoxicity:** Most neurotoxicity studies in rats use high doses of racemic or d-methamphetamine; some data are extrapolated to d-amphetamine based on class membership. Thomas et al. (2004) specifically included D-amphetamine alongside D-methamphetamine as causing microglial activation [Ref 18], but chronic neurotoxicity threshold doses for d-amphetamine in humans are not established.

7. **Dependence/tolerance data are largely class-level:** Most published dependence and sensitization studies use racemic amphetamine or methamphetamine; dextroamphetamine-specific controlled longitudinal studies are limited.

### Safety-Critical Flags

**FLAG 1 — Tramadol interaction ("lethal" in brief):** The brief rates the tramadol interaction as "lethal." No published case report specifically documenting a dextroamphetamine + tramadol fatality was found in indexed literature. The pharmacological mechanism (combined serotonin agonism/release + SERT inhibition by tramadol → serotonin syndrome) makes this interaction genuinely dangerous. However, classifying it as "lethal" rather than "dangerous" may overstate the certainty of outcome. Recommend editorial reclassification to "dangerous" with a note on serotonin syndrome risk, pending identification of case report evidence.

**FLAG 2 — PCP interaction ("dangerous" in brief):** Pharmacologically plausible (additive dopaminergic/psychomimetic potentiation) but not confirmed by a specific published study in indexed literature. The "dangerous" rating is reasonable but should be flagged as inferred from mechanism.

**FLAG 3 — Characterization as "emerging" in the brief (CRITICAL):** The brief seed data characterizes dextroamphetamine as "emerging." This appears to be a database error. Dextroamphetamine has been in clinical use since the 1930s, is FDA-approved, has hundreds of published RCTs, and is one of the most extensively studied psychostimulants in medical history. This characterization must be corrected. Recommend "classic" or "established" as the correct characterization.

**FLAG 4 — Primary ROA listed as "insufflated" in the brief:** The brief states primary ROA as insufflated. Clinically and historically, the primary route of administration is oral (as prescribed). Insufflated is a common recreational route but is not the primary route for this substance by any standard metric (prescription data, published studies, or harm reduction literature). Recommend correcting to oral as primary ROA, with insufflated as a secondary known route. This discrepancy should be reviewed.

**FLAG 5 — Dose sensitivity field empty:** The brief has no dose sensitivity data. Given the well-established therapeutic dose ranges (5–40 mg/day, weight-independent in most clinical contexts) and the significant inter-individual variability documented with DAT pharmacogenomics [Ref 17], this warrants dose sensitivity classification. Recommend editorial review.

**FLAG 6 — Toxicity notes in brief ("Inferred from pharmacological class — not sourced from literature"):** The toxicity classification (acute: moderate, chronic: moderate) with the note "not sourced from literature" should be reviewed. Published data supports the cardiovascular risk and neurotoxicity at high doses as evidence for at least "moderate" acute and chronic toxicity, but a more specific sourced assessment is needed.

### Dose/Duration Assessment

**Oral doses (from clinical and controlled studies):**
- Therapeutic ADHD doses: 5–40 mg/day (children), up to 60 mg/day (adults, extended-release) [Ref 21]
- Controlled human lab studies: 10 mg and 20 mg oral doses are well-characterized [Ref 17, Ref 26]
- SKAMP studies with d-ATS: 5, 10, 15, 20 mg patches [Ref 6]
- Narcolepsy: 5–60 mg/day in divided doses [Ref 21]

The brief's dose ranges (threshold 3.75 mg, light 3.75–10 mg, common 10–16 mg, strong 16–30 mg, heavy 30+ mg oral) are consistent with the clinical and controlled study data. No published source contradicts these ranges. They appear well-calibrated for healthy adult recreational/non-prescribed use.

**Duration data:** The brief's oral duration data (onset 15–30 min, come-up 30–60 min, peak 2.5–4 h, offset 2–3 h, aftereffects 3–6 h, total 6–8 h) is consistent with immediate-release Dexedrine's 4–6 hour clinical duration and the Tmax of ~3 hours. No contradiction with published data.

**Insufflated duration** (onset 1–5 min, come-up 5–15 min, peak 1–2 h, offset 1.5–3 h, aftereffects 2–4 h, total 3–6 h) is consistent with faster absorption via nasal mucosa. Consistent with pharmacokinetic expectations.