TCP (Tenocyclidine)
Tenocyclidine (TCP) is a thiophene analogue of PCP in which the phenyl ring is replaced by a thienyl group. It is a potent NMDA receptor antagonist studied largely in preclinical pharmacology as a research tool, with essentially no controlled human data. It shares PCP's dissociative and psychotomimetic profile and is reported to be more potent.
01 Overview
TCP was investigated chiefly as a laboratory ligand for NMDA receptor and dopamine transporter studies rather than as a medicine. Human exposure is confined to sporadic recreational use of grey-market material, and its pharmacology in people is inferred largely from PCP and animal work.
As a more potent PCP analogue, TCP would be expected to produce dose-dependent dissociation, ataxia, anaesthesia and, at higher doses, agitation and psychosis. Its narrow characterisation and high potency make dosing especially uncertain, and redosing on an ill-defined duration raises overdose risk.
02 Mechanism
Non-competitive NMDA receptor open-channel blocker; also inhibits the dopamine transporter, contributing to stimulant and psychotomimetic effects.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Light (uncertain) | 1–3 mg | Insufflated | Poorly characterised; caution due to potency. |
| Common (uncertain) | 2–6 mg | Oral | Estimated from anecdote; potency higher than PCP. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| DissociationDetachment, depersonalisation and derealisation similar to PCP. | Anecdotal | ||
| AnalgesiaReduced pain perception inferred from animal and analogue data. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Agitation and psychosisParanoia, agitation and dissociative psychosis expected by analogy to PCP. | Severe | Unknown | Unconfirmed | |
| Ataxia and anaesthesiaLoss of coordination progressing to dissociative anaesthesia at higher doses. | Moderate | Dose-dependent | Unconfirmed |