Diphenidine
Diphenidine (DPD) is a diarylethylamine dissociative that appeared as a research chemical around 2013, often alongside methoxphenidine. It is an NMDA receptor antagonist producing dose-dependent dissociation, stimulation and anaesthesia. Human data are limited to case reports and anecdote, and it has featured in several intoxication and death investigations.
01 Overview
Diphenidine is the parent diarylethylamine of the methoxphenidine family and was distributed as a legal dissociative when ketamine analogues were restricted. It is usually taken orally and has a relatively long duration with a slow onset.
Effects scale with dose from stimulation and mild dissociation to heavy dissociative anaesthesia, ataxia, confusion and cardiovascular stimulation. As with MXP, delayed onset has driven accidental redosing and overdose. It has been detected in post-mortem toxicology in combination-drug deaths.
02 Mechanism
Non-competitive NMDA receptor antagonist binding the PCP site within the channel; a diarylethylamine rather than an arylcyclohexylamine.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Light | 30–50 mg | Oral | Slow onset; wait before considering more. |
| Common | 50–100 mg | Oral | Delayed onset drives accidental redosing. |
| Strong | 100–150 mg | Oral | Heavy dissociation and confusion. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| DissociationDetachment, depersonalisation and derealisation. | Anecdotal | ||
| StimulationEnergising effect reported at lower doses. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Confusion and disorientationDisorientation, agitation and confusion reported in intoxications. | Moderate | At higher doses | Observational | |
| Ataxia and loss of coordinationUnsteady gait and impaired motor control with fall risk. | Moderate | Very common | Anecdotal | |
| Cardiovascular stimulationRaised heart rate and blood pressure reported. | Moderate | Common | Observational |