High doses of dextromethorphan, an NMDA antagonist, produce effects similar to classic hallucinogens.
Psychopharmacology September 1, 2012 Chad J Reissig, Lawrence P Carter, Matthew W Johnson et al. 89 citations
High doses of the cough suppressant dextromethorphan (DXM) produce perceptual changes, mystical-type experiences, and physiological effects similar to those of classic hallucinogens like psilocybin. In a double-blind study, 12 healthy volunteers with histories of hallucinogen use received single oral doses of DXM ranging from 100 to 800 mg/70 kg, triazolam, or placebo. DXM dose-dependently increased blood pressure, heart rate, and emesis, and elicited observer-rated hallucinogen-like effects such as visual distortions and joy. After 400 mg/70 kg DXM, 11 of 12 participants thought they had received a classic hallucinogen. At a 1-month follow-up, volunteers reported lasting positive changes in spirituality, attitudes, and mood attributed to the session.