Over-the-counter (OTC) medicines are those that can be sold directly to people without a prescription. OTC medicines treat a variety of illnesses and their symptoms including pain, coughs and colds, diarrhea, constipation, acne, and others. Some OTC medicines have active ingredients with the potential for misuse at higher-than-recommended dosages.

Dextromethorphan (DXM) is a cough suppressant found in many OTC cold medicines. The most common sources of abused DXM are “extra-strength” cough syrup, tablets and gel capsules. OTC medications that contain DXM often also contain antihistamines and decongestants. DXM may be swallowed in its original form or may be mixed with soda for flavor, called “robo-tripping” or “skittling.” Users sometimes inject it. These medicines are often misused in combination with other drugs, such as alcohol and marijuana.