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Rolicyclidine Facts

Dissociative; Arylcyclohexylamine; NMDA receptor antagonist

Description

Rolicyclidine (1-phenylcyclohexylpyrrolidine) — PHP, PCPy — is a synthetic dissociative of the arylcyclohexylamine class. It sits between ketamine and PCP in potency.[1] It blocks glutamate signaling in the brain, producing a fragmented dissociative state where perception and conscious awareness come apart.

Synthesized in 1958 by Parke-Davis chemists,[2] rolicyclidine was never developed for medical use. It appeared briefly on US street markets in the late 1970s as a PCP substitute,[3] generating a handful of clinical case reports before disappearing. It is now rarely encountered and internationally controlled under Schedule I.

Subjective effects include hallucinations, agitation, thought disorganization, motor impairment, and physical disconnection from the body.[4][5] The experience closely parallels PCP intoxication — perception fragments, thinking falls apart, and the body feels distant or uncontrollable. Paranoid thinking, involuntary movements, and episodes of acute psychosis are characteristic unwanted outcomes.

Physical dependence is inferred from PCP-class animal data,[6] and no lethal dose has been established. safety citation needed Rolicyclidine also permanently disables liver enzymes,[7] causing other drugs to accumulate to dangerous levels for days after use. The evidence base is extremely thin — almost everything known comes from a handful of case reports and animal studies, not controlled human research.

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 1 mgLight2 – 3 mgCommon4 – 8 mgStrong8 – 12 mgHeavy14+ mg

Starts in 20 – 90 minLasts 6 – 12 hoursAfter-effects 4 – 12 hours

Body and dependence

Acute toxicity
Low
Chronic toxicity
Low
Physical dependence
Moderate
Psychological dependence
Moderate
Withdrawal
Moderate
Compulsive redosing
Moderate

Tolerance

Builds
Moderate
Fully resets after
10 days
Carries over to
phencyclidine; ketamine; eticyclidine; tenocyclidine; 3-MeO-PCP; 3-MeO-PCE; deschloroketamine

Effectslikely at a common dose

Perception
Touch suppression; Proprioceptive distortion; Spatial disorientation; Vestibular distortion; +14 possible, including Visual acuity suppression, Visual haze / noise, Double vision
Body
Pain suppression; Dizziness; Motor control impairment; Body schema distortion; Nystagmus (eye wobbles); +28 possible, including Nausea, Temperature dysregulation, Excessive sweating
Thinking
Analysis suppression; Memory suppression; Thought disorganization; Cognitive impairment; Confusion; Decision impairment; Focus suppression; Information processing suppression; +19 possible, including Language suppression, Compulsive redosing urge, Cognitive dysphoria
Feeling
none likely · 12 possible, including Anxiety, Emotional lability, Paranoia
Self
Depersonalization; Derealization; +7 possible, including Social disconnection, Ego inflation, Communication suppression
Time
Time alteration; Temporal disorientation; +2 possible

Who shouldn't take it

Absolute
Psychotic disorders; Pregnancy
Relative
Cardiovascular disease; Respiratory compromise; Epilepsy; Bipolar disorder; Hepatic impairment

Combinations63 recorded

Lethal (4)
GHB, GBL; Ibogaine; Tramadol; αMT
Dangerous (36)
Amphetamines; Benzodiazepines; Buprenorphine, Kratom; Ephedrine, Pseudoephedrine; MDMA, Amphetamines; Naltrexone; NDRIs (Wellbutrin); NRIs; NSAIDs; Opioids; THC; Anticholinergics; Antihistamines; Atypical antipsychotics; Benzodiazepines, Barbiturates; Buspirone; Caffeine; Clonidine, Guanfacine; Dopamine agonists; DXM; Gabapentin, Pregabalin; GHB, Baclofen; Ketamine, DXM, PCP; Lithium; and 12 more, see full page
Caution (20)
See full page: psychedex.org/substances/rolicyclidine
Not graded (3)
Not listed never means safe.

Seek help immediately if

  • Severe disorientation; unable to move or speak (deep dissociation / "k-hole")
  • Complete loss of coordination — cannot stand or walk safely
  • Vomiting while incapacitated (choking / aspiration risk)
  • Very high blood pressure; fast heart rate
  • Slow or shallow breathing at high doses (especially mixed with depressants)
  • Unconsciousness; rarely, seizures

What to do

  1. Move them somewhere safe, away from stairs, water, roads, and sharp edges — they cannot protect themselves
  2. Place in the recovery position if vomiting or unconscious (aspiration is a key risk)
  3. Stay with them and reassure calmly; keep the environment quiet
  4. If breathing is slow/shallow or they are unresponsive, call emergency services
  5. Do not let them wander; do not leave them alone
  6. Be ready to give rescue breaths / CPR

Effects wear off with time in a safe, monitored setting. The main dangers are physical injury and aspiration while incapacitated, and respiratory depression when combined with other depressants — not the dissociation itself.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Brady KT, Balster RL (1981) Discriminative stimulus properties of phencyclidine and five analogues in the squirrel monkey. — Pharmacology, Biochemistry, and Behavior PMID:7208560
  2. [2]
    ^National Center for Advancing Translational Sciences (2023) Rolicyclidine - NCATS Inxight Drugs Link
  3. [3]
    ^Budd RD (1980) PHP, a new drug of abuse. — The New England Journal of Medicine PMID:7402231
  4. [4]
    ^Giannini AJ, Castellani S (1982) A case of phenylcyclohexylpyrrolidine (PHP) intoxication treated with physostigmine. — Journal of Toxicology. Clinical Toxicology PMID:7175996
  5. [5]
    ^Giannini AJ, Price WA, Loiselle RH, Malone DW (1985) Treatment of phenylcyclohexylpyrrolidine (PHP) psychosis with haloperidol. — Journal of Toxicology. Clinical Toxicology PMID:4057312
  6. [6]
    ^Perry JL, Normile LM, Morgan AD, Carroll ME (2006) Sex differences in physical dependence on orally self-administered phencyclidine (PCP) in rhesus monkeys — Experimental and Clinical Psychopharmacology PMID:16503706
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