Final rule · 2026-19231

Schedules of Controlled Substances: Placement of Diphenidine in Schedule I

With the issuance of this final rule, the Drug Enforcement Administration places the substance diphenidine (1-(1,2- diphenylethyl)piperidine), including its salts, isomers, and salts of isomers whenever the existence of such salts, isomers, and salts of isomers is possible, in schedule I of the Controlled Substances Act. This action is being taken, in part, to enable the United States to meet its obligations under the 1971 Convention on Psychotropic Substances. This action imposes the regulatory controls and administrative, civil, and criminal sanctions applicable to schedule I controlled substances on persons who handle (manufacture, distribute, reverse distribute, import, export, engage in research, conduct instructional activities or chemical analysis with, or possess) or propose to handle diphenidine.