Dextromethorphan, also known as DXM, the active ingredient in most Robitussin products, is an antitussive drug that acts as a dissociative hallucinogen at high doses.
DXM is legal and over-the-counter in much of the world, although some jurisdictions require customers to be 18 to purchase it, and/or limit the maximum amount to be purchased.
The magnitude of the effects of DXM varies from individual to individual. In those who have lower levels of the enzyme CYP-2D6, the effects are much stronger. The prevalence of CYP-2D6 deficiency is approximately 6-10% in Caucasian populations, 2% in Asian populations, and "greater than 10%" in African populations. For those seeking to use DXM recreationally, it is recommended to try a smaller dose beforehand, as poor metabolizers will usually get a significant psychoactive effect, while typical metabolizers will not.
The recreational use of dextromethorphan itself, without other medications, is relatively safe. However, combining it with other drugs may cause dangerous interactions, such as Serotonin Syndrome.
Furthermore, it is critical to read the label of dextromethorphan preparations. It is frequently paired with pain relievers, decongestants, and expectorants, all of which can be dangerous or fatal at high doses.