Dextromethorphan (DXM or DM) is an antitussive (cough suppressant) drug. It is one of the active ingredients in many over-the-counter cold and cough medicines, such as Mucinex DM, Robitussin, NyQuil, Dimetapp, Vicks, Coricidin, Delsym, TheraFlu, and others, including generic labels. Dextromethorphan has also found other uses in medicine, ranging from pain relief to psychological applications. It is sold in syrup, tablet, spray, and lozenge forms. In its pure form, dextromethorphan occurs as a white powder and is unstable. Due to this instability pure dxm degrades over time and loses its purity. DXM is also used recreationally. When exceeding label-specified maximum dosages, dextromethorphan acts as a dissociative hallucinogen. Its mechanism of action is via multiple effects, including actions as a nonselective serotonin reuptake inhibitor and a sigma-1 receptor agonist. The major metabolite of DXM, dextrorphan, also acts as an NMDA receptor antagonist.
Contributions by Equazcion, RJSampson, and Beetstra.