3-HO-PCP

3-HO-PCP (3-hydroxyphencyclidine) is a synthetic dissociative of the arylcyclohexylamine class, a hydroxylated analog of phencyclidine (PCP). It is pharmacologically distinguished from most other dissociatives by its dual mechanism: potent NMDA receptor antagonism combined with significant mu-opioid receptor agonist activity. This dual pharmacology makes 3-HO-PCP substantially more dangerous than ketamine or PCP analogs that lack opioid activity, and places it in a risk category comparable to opioid-dissociative polydrug combinations.

Community experience with 3-HO-PCP is substantial relative to its obscurity — the Reddit community contains numerous discussion threads covering its unusual warmth and euphoria (attributable to opioid activity), its potential for compulsive use, its paradoxical combination of dissociative and opiate-like qualities, and several cautionary accounts including one describing a 50 mg experience as psychologically extreme ("A Clockwork Tan"). Multiple discussions address the risk of opioid withdrawal reactivation in individuals with prior opioid use disorder — a clinically critical concern. Community members consistently compare it favorably to other dissociatives for euphoria while acknowledging it is among the most physiologically hazardous in the class.

The opioid activity gives 3-HO-PCP overdose characteristics distinct from pure dissociatives: respiratory depression can occur at doses that produce intense dissociation, and the combination with other opioids or CNS depressants can be fatal. Naloxone can partially reverse 3-HO-PCP effects, but incomplete reversal of NMDA antagonism means it may not fully resolve an overdose.