IUPAC Name
6-(2-chlorophenyl)-1-methyl-8-nitro-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine
Current Scheduling Status
Year(s) and type of review / ECDD meetings
Drug Class
Recommendation (from TRS)
Substance identification
Diphenidine (chemical name: 1-(1,2-diphenylethyl)piperidine) is a dissociative and hallucinogenic substance of the 1,2-diarylethylamine class. It is found as a powder and in tablets.
WHO review history
Diphenidine has not been formally reviewed by WHO and is not currently under international control. Information was brought to WHO’s attention that this substance is manufactured clandestinely, poses a risk to public health and has no recognized therapeutic use.
Similarity to known substances and effects on the central nervous system
Diphenidine is known to produce hallucinogenic and dissociative effects through its action as an NMDA receptor antagonist. This mechanism of action and its effects are similar to those of PCP, which is controlled under Schedule II of the 1971 Convention on Psychotropic Substances.
Dependence potential
No studies have been reported in animals or humans on the dependence potential of diphenidine.
Actual abuse and/or evidence of likelihood of abuse
As diphenidine is an NMDA receptor antagonist, it would be expected to have abuse potential similar to that of PCP. In addition, diphenidine causes the release of dopamine, in a manner similar to but to a lesser degree than cocaine. This effect may also contribute to its abuse potential. Cases of intoxication requiring hospitalization have been reported. Adverse effects include cardiovascular effects (such as tachycardia and hypertension) and central nervous system effects, including hallucinations, depersonalization, delusions, paranoia, dissociation, confusion, nystagmus and muscle rigidity. These effects have resulted in acute intoxication requiring emergency admission. A small number of fatal intoxications involving diphenidine have been documented. All the deaths involved multiple drugs; however, the cardiovascular and hallucinogenic symptoms described were consistent with the effects of diphenidine. Seizures have been reported in a number of countries in several regions.
Therapeutic usefulness
Diphenidine is not known to have any therapeutic use.
Recommendation
The available evidence indicates that the mechanism of action and effects of diphenidine (chemical name: 1-(1,2-diphenylethyl)piperidine) are similar to those of PCP, which is controlled under Schedule II of the 1971 Convention on Psychotropic Substances. Its mode of action suggests the potential for abuse. There is evidence that diphenidine causes significant harm, including psychosis and cardiovascular effects, representing a substantial risk to public health. Diphenidine has no therapeutic use.
Recommendation: The Committee recommended that diphenidine (chemical name: 1-(1,2-diphenylethyl)piperidine) be added to Schedule II of the Convention on Psychotropic Substances of 1971.
Diphenidine (chemical name: 1-(1,2-diphenylethyl)piperidine) is a dissociative and hallucinogenic substance of the 1,2-diarylethylamine class. It is found as a powder and in tablets.
WHO review history
Diphenidine has not been formally reviewed by WHO and is not currently under international control. Information was brought to WHO’s attention that this substance is manufactured clandestinely, poses a risk to public health and has no recognized therapeutic use.
Similarity to known substances and effects on the central nervous system
Diphenidine is known to produce hallucinogenic and dissociative effects through its action as an NMDA receptor antagonist. This mechanism of action and its effects are similar to those of PCP, which is controlled under Schedule II of the 1971 Convention on Psychotropic Substances.
Dependence potential
No studies have been reported in animals or humans on the dependence potential of diphenidine.
Actual abuse and/or evidence of likelihood of abuse
As diphenidine is an NMDA receptor antagonist, it would be expected to have abuse potential similar to that of PCP. In addition, diphenidine causes the release of dopamine, in a manner similar to but to a lesser degree than cocaine. This effect may also contribute to its abuse potential. Cases of intoxication requiring hospitalization have been reported. Adverse effects include cardiovascular effects (such as tachycardia and hypertension) and central nervous system effects, including hallucinations, depersonalization, delusions, paranoia, dissociation, confusion, nystagmus and muscle rigidity. These effects have resulted in acute intoxication requiring emergency admission. A small number of fatal intoxications involving diphenidine have been documented. All the deaths involved multiple drugs; however, the cardiovascular and hallucinogenic symptoms described were consistent with the effects of diphenidine. Seizures have been reported in a number of countries in several regions.
Therapeutic usefulness
Diphenidine is not known to have any therapeutic use.
Recommendation
The available evidence indicates that the mechanism of action and effects of diphenidine (chemical name: 1-(1,2-diphenylethyl)piperidine) are similar to those of PCP, which is controlled under Schedule II of the 1971 Convention on Psychotropic Substances. Its mode of action suggests the potential for abuse. There is evidence that diphenidine causes significant harm, including psychosis and cardiovascular effects, representing a substantial risk to public health. Diphenidine has no therapeutic use.
Recommendation: The Committee recommended that diphenidine (chemical name: 1-(1,2-diphenylethyl)piperidine) be added to Schedule II of the Convention on Psychotropic Substances of 1971.
ECDD Recommendation
Inclusion in Schedule II of the 1971 Convention on Psychotropic Substances
Link to full TRS
9789240023024-eng.pdf1.84 MB
MS Questionnaire Report