Dextrorphan is a substance currently unclassified in the ARCI’s Uniform Classification of Foreign Substances.
Dextrorphan is a metabolite of dextromethorphan (4/B), a cough suppressant that is commercially available with FDA-approved for human use in over-the-counter, tablet and oral syrup formulations (e.g. Robitussin DM). It is a component of combination products (e.g. Mucinex) with guaifenesin (4/C), an expectorant that is listed on the Schedule of Controlled Therapeutic Substances. Dextromethorphan is also a substance of human abuse. When consumed in large doses, its dose-dependent effects range from euphoria to hallucinations, dissociative (out-of-body) experiences, coma, and death.
The Racing Medication and Testing Consortium recommends a 4-B classification for this substance.