3-Hydroxyphencyclidine (3-HO-PCP) is a dissociative hallucinogen of the arylcyclohexylamine class related to phencyclidine (PCP) that has been sold online as a designer drug.
3-HO-PCP acts as a high-affinity uncompetitive antagonist of the NMDA receptor via the dizocilpine (MK-801) site (Ki = 30 nM). It has much higher affinity than PCP for this site (Ki = 250 nM, for comparison; 8-fold difference). The drug also has high affinity for the μ-opioid receptor (MOR) (Ki = 39–60 nM),the κ-opioid receptor (KOR) (Ki = 140 nM), and the sigma σ1 receptor (Ki = 42 nM; IC50 = 19 nM), whereas it has only low affinity for the δ-opioid receptor (Ki = 2,300 nM). The high affinity of 3-HO-PCP for opioid receptors is unique among arylcyclohexylamines and is in contrast to PCP, which has only very low affinity for the MOR (Ki = 11,000–26,000 nM; 282- to 433-fold difference) and the other opioid receptors (Ki = 4,100 nM for the KOR and 73,000 nM for the DOR).
3-HO-PCP is legal in Germany.