O-PCE (2-Oxo-PCE): Complete Intoxication, Metabolism, Dependence & Safety Monograph

O-PCE (2-Oxo-PCE): Complete Intoxication, Metabolism, Dependence & Safety Monograph

Emergency dissociative toxicity: Seizure, collapse, inability to awaken, severe confusion/agitation, abnormal breathing, dangerous injury risk, chest pain, or prolonged inability to safely care for oneself after O-PCE or an unknown dissociative warrants urgent medical assessment.

Quick answer

O-PCE is an arylcyclohexylamine dissociative closely related to ketamine-family and phencyclidine-family compounds, with direct evidence of severe human poisoning and fatalities.

It is also called:

• 2-oxo-PCE;
• 2'-oxo-PCE;
• N-ethyldeschloroketamine;
• deschloro-N-ethyl-ketamine;
• eticyclidone.

The best human evidence includes a 56-case analytically confirmed poisoning cluster and newer toxicokinetic/metabolism work.

O-PCE intoxication can produce:

• profound dissociation;
• impaired consciousness;
• confusion;
• abnormal behavior;
• hypertension;
• tachycardia;
• convulsions;
• prolonged recovery.

Identity and chemistry

O-PCE should not be confused with:

• 3-MeO-PCE;
• 2F-DCK;
• deschloroketamine (DCK);
• 2-fluoro-2-oxo-PCE / CanKet.

Similar names do not mean identical pharmacology, metabolism, or legal status.

History

O-PCE is a ketamine/PCP-related arylcyclohexylamine that appeared in modern NPS markets in the mid-2010s.

A major clinical signal emerged in Hong Kong in 2017, when hospitals encountered a cluster of ketamine-like poisonings in which bedside ketamine testing was negative.

Mass-spectrometric investigation identified O-PCE.

That outbreak is a textbook example of why clinical toxidromes can precede routine laboratory recognition of an NPS.

Pharmacology

Arylcyclohexylamine dissociatives generally reduce excitatory glutamatergic signaling through NMDA receptor antagonism.

This can produce:

• dissociation;
• analgesia;
• altered sensory integration;
• impaired memory;
• ataxia;
• distorted body perception;
• reduced responsiveness;
• delirium/behavioral disorganization at higher exposure.

O-PCE-specific human receptor occupancy and dose-response studies are absent.

Do not import ketamine dosing or potency

Structural relatedness to ketamine does not create a valid conversion.

Differences in:

• N-substitution;
• dechlorination;
• metabolism;
• lipophilicity;
• active metabolites

can materially alter onset, duration, potency, and toxicity.

The 56-case Hong Kong poisoning cluster

Between October and November 2017, investigators identified 56 O-PCE-associated acute poisonings.

O-PCE was analytically confirmed in urine in all cases.

Other drugs were detected in 55%, leaving a substantial subgroup in which O-PCE was used alone.

Among sole O-PCE cases:

• impaired consciousness: 84%;
• confusion: 60%;
• abnormal behavior: 44%;
• hypertension: 80%;
• tachycardia: 40%;
• convulsions: 16%.

Three patients required intensive care.

All recovered with mainly supportive treatment.

Why convulsions matter

Convulsions occurred often enough in the O-PCE-only subgroup to be a real compound-specific safety signal.

A seizure can also trigger:

• aspiration;
• injury;
• rhabdomyolysis;
• lactic acidosis;
• prolonged altered consciousness.

A first or recurrent seizure is an emergency.

Prolonged dissociation and behavioral risk

Severe dissociative intoxication can make a person:

• unable to recognize hazards;
• unable to walk safely;
• confused about surroundings;
• behaviorally unpredictable;
• amnestic;
• vulnerable to falls, traffic injury, drowning or exposure.

“Conscious” does not necessarily mean capable of self-protection.

Cardiovascular findings

The Hong Kong cluster directly documented:

• hypertension;
• tachycardia.

These may reflect:

• NMDA-antagonist/sympathomimetic effects;
• agitation;
• stress response;
• co-drugs.

O-PCE should not be treated as a purely sedating anesthetic-type exposure.

Human toxicokinetics: one 2024 case

A 2024 study used serial plasma samples from a multidrug user to characterize O-PCE toxicokinetics.

The estimated elimination half-life was about five hours.

Researchers also annotated 27 metabolites, including previously unreported phase-II compounds.

Why that half-life is not a duration timer

The estimate comes from one multidrug case.

It does not define:

• population variability;
• intoxication duration;
• repeated-dose accumulation;
• effects of liver/kidney disease;
• a safe driving interval;
• a redosing interval.

Human data improved, but remain sparse.

Metabolism

A 2021 metabolism study used pooled human liver microsomes plus authentic urine and hair.

Researchers identified 15 metabolites overall.

Suggested urinary targets included several glucuronidated and hydroxylated metabolites.

Critically, parent O-PCE was no longer detected in urine while multiple metabolites remained present.

That means metabolite-aware testing can materially extend the exposure-detection window.

Hair testing and long-term exposure markers

Hair can preserve evidence over a longer period than blood or urine.

In the metabolism study, hydroxylated metabolites were particularly useful for hair interpretation.

Hair detection can support prior exposure but does not establish impairment at a particular time.

Fatality evidence

A published fatal case involved O-PCE with venlafaxine and evidence of other drugs/substances.

O-PCE was quantified across:

• femoral/heart blood;
• liver;
• urine;
• bile;
• gastric contents;
• cerebrospinal fluid.

The case is important for showing postmortem distribution.

It does not establish an O-PCE-only lethal concentration because the death was polysubstance and postmortem concentrations varied markedly across tissues.

Interactions

Alcohol/benzodiazepines/opioids

Can increase:

• impaired consciousness;
• aspiration risk;
• respiratory compromise;
• accidents.

Other dissociatives

Can intensify:

• confusion;
• hypertension;
• motor impairment;
• amnesia;
• psychosis/delirium.

Stimulants

May increase cardiovascular strain while not preventing dissociative impairment.

Serotonergic drugs

O-PCE is not best characterized as a serotonergic drug, but polysubstance NPS use can include serotonergic compounds. The fatal venlafaxine case is a reminder that combined toxicity must be interpreted by actual co-exposures rather than a single interaction slogan.

Dependence and compulsive use

Human O-PCE dependence epidemiology is absent.

However, repeated dissociative use can become compulsive, and a 2024 O-PCE toxicokinetic/metabolism case occurred in a multidrug user with repeated NPS exposure.

The responsible evidence statement is:

• abuse/dependence liability is credible;
• O-PCE-specific incidence is unknown;
• there is no validated threshold at which dependence occurs.

Withdrawal

Ketamine/dissociative withdrawal is usually characterized more by psychiatric/behavioral symptoms than by the classic seizure-delirium syndrome of alcohol or benzodiazepines.

Possible class-level symptoms after heavy repeated use can include:

• craving;
• anxiety;
• restlessness;
• low mood;
• sleep disturbance;
• irritability.

O-PCE-specific withdrawal studies are not available.

Therefore the page should not claim a precise onset, duration, or taper protocol.

Ketamine-associated urinary tract toxicity: what can and cannot be inferred

Chronic ketamine exposure is strongly associated with ketamine-induced cystitis/uropathy.

Symptoms can include:

• urinary frequency/urgency;
• painful urination;
• bladder pain;
• blood in urine;
• reduced bladder capacity;
• upper-tract injury in severe disease.

2024 French and British urology guidance emphasizes early recognition and stopping ketamine exposure as central to management.

Does that prove O-PCE causes the same bladder disease?

No.

There is insufficient O-PCE-specific epidemiology to quantify cystitis risk.

But persistent urinary symptoms in a frequent arylcyclohexylamine user deserve medical evaluation because:

1. severe ketamine uropathy is established;
2. O-PCE is chemically/pharmacologically related;
3. absence of O-PCE-specific case series is not proof of safety.

This is class-informed caution, not a claim of measured O-PCE incidence.

Treatment and support

There is no approved medication specifically for O-PCE use disorder or withdrawal.

Care can include:

• acute supportive management;
• treatment of seizures/agitation/cardiovascular complications;
• addiction-medicine assessment for compulsive use;
• psychiatric care for persistent psychosis/depression;
• urologic evaluation for urinary symptoms.

U.S. resources:

• FindTreatment.gov
• SAMHSA National Helpline: 1-800-662-HELP (4357)

Drug testing: a major blind spot

Ketamine immunoassay

In the 2017 outbreak, bedside urine ketamine immunoassay did not cross-react with O-PCE.

So:

a negative ketamine screen does not rule out O-PCE.

Routine NPS panels

Whether O-PCE is found depends on:

• the analyte library;
• detection limits;
• parent vs metabolite targets;
• specimen timing.

Definitive testing

Useful methods include:

• LC-MS/MS;
• LC-HRMS/QTOF;
• GC-MS in validated workflows;
• metabolite-aware urine analysis;
• hair analysis for longer-term exposure.

Forensic interpretation

Parent absent, metabolites present

Urine can remain useful after parent O-PCE is gone if the laboratory includes validated metabolites.

Blood concentration is not a dose

Concentration depends on:

• timing;
• route;
• tolerance;
• co-drugs;
• distribution;
• metabolism.

Postmortem redistribution/distribution

The fatal case showed large concentration differences between blood and tissues.

That is exactly why a liver/heart-blood/femoral-blood value cannot be turned into a personal lethal-dose chart.

Special populations

Controlled O-PCE data are inadequate for:

• pregnancy/breastfeeding;
• adolescents;
• older adults;
• cardiovascular disease;
• seizure disorders;
• psychiatric illness;
• liver/kidney disease.

People with seizure history, serious cardiovascular disease, or psychosis vulnerability may plausibly face higher risk, but compound-specific magnitudes are not established.

Legal context — verified October 2, 2026

Legal status for O-PCE varies by jurisdiction.

UNODC EWA lists O-PCE as a phencyclidine-type NPS but its substance record does not show an international 1971-Convention scheduling status as of this review date.

In the U.S. primary federal sources reviewed for this monograph, O-PCE was not identified as a molecule-specific CSA listing comparable to the May 2026 temporary Schedule I action for 2F-DCK.

That does not mean possession/distribution is necessarily lawful:

• federal analogue law can apply depending on chemical/pharmacological similarity, intended human consumption and case-specific facts;
• state laws can separately control it.

This is legal-status information, not legal advice.

Myths and misconceptions

“O-PCE is just stronger ketamine.”
Oversimplified. It has distinct metabolism, duration and human toxicity evidence.

“If the ketamine screen is negative, O-PCE is ruled out.”
False. Direct human outbreak data show otherwise.

“The five-hour half-life tells you exactly how long effects last.”
False. It comes from one multidrug case and does not equal functional recovery.

“No proven O-PCE cystitis epidemic means the bladder risk is zero.”
Not established. Ketamine uropathy is a class warning, but O-PCE-specific incidence is unknown.

“A postmortem blood number gives a lethal dose.”
False.

“Dependence has been quantified.”
No. Dependence liability is credible, but O-PCE-specific incidence and withdrawal course remain sparse.

Evidence ledger

Related evidence

• 2F-DCK / 2-Fluorodeschloroketamine
• Deschloroketamine / DCK
• 3-MeO-PCE
• Methoxetamine / MXE
• Dissociatives & arylcyclohexylamines guide
• Substance Use, Dependence & Harm Reduction hub

Bottom line

O-PCE has enough human evidence that it should not be described as a mystery dissociative.

A 56-case outbreak directly documents loss of consciousness, confusion, hypertension, tachycardia and convulsions; newer work adds human toxicokinetics and a much better metabolite map.

The major uncertainties are chronic rather than acute: dependence incidence, long-term organ effects and whether ketamine-like urinary toxicity translates quantitatively to O-PCE.

That uncertainty belongs on the page just as prominently as the known acute hazards.