Diphenidine (1-(1,2-diphenylethyl)piperidine) is a dissociative anesthetic drug that has been sold online as a research chemical. The synthesis of diphenidine was first reported in 1924, and employed a nitrile displacement reaction analogous to the one that would later be used to discover phencyclidine in 1956. Shortly after the 2013 UK ban on arylcyclohexylamines, diphenidine and the related compound methoxphenidine became available on the gray market. Anecdotal reports describe high doses of diphenidine producing "bizarre somatosensory phenomena and transient anterograde amnesia." Diphenidine and related diarylethylamines have been studied in vitro as treatments for neurotoxic injury and are antagonists of the NMDA receptor. Recent electrophysiological analysis demonstrates that the amplitude of NMDA-mediated fEPSPs are reduced by diphenidine and ketamine to a similar extent, with diphenidine displaying a slower onset of antagonism. Though vendors of diphenidine have stated the compound "acts on dopamine transport" to date diphenidine has not been screened for affinity at the dopamine transporter. In dogs diphenidine exhibits greater antitussive potency than codeine phosphate.
Since 2014 there have been several published reports of diphenidine being sold in combination with synthetic cannabinoids in Japanese herbal incense blends. A herbal incense sold in the Shizuoka Prefecture under the name "Aladdin (sic) Spacial Edition" was found to contain diphenidine and 5-fluoro-AB-PINACA at concentrations of 289 mg/g and 55.5 mg/g, respectively. Another product called ‘‘Herbal Incense. The Super Lemon’’ containing AB-CHMINACA, 5F-AMB, and diphenidine was implicated in a fatal overdose.
See also
- Methoxphenidine (MXP)
- Lanicemine
- Lefetamine
- MT-45