DXM

Dextromethorphan, usually called DXM, is a cough suppressant found in many over-the-counter cold and cough medicines, sold as syrups, capsules, and tablets. At the doses on the label it is a safe, effective, and widely used remedy for temporary coughs. At much higher doses, however, DXM acts as a dissociative drug, producing effects similar to ketamine or PCP, which is why it is sometimes misused — a practice often called 'robotripping.' Because DXM is legal and easy to buy, misuse is most common among adolescents and young adults. A key danger is that many products contain DXM combined with other active ingredients, so taking a large amount to feel DXM's effects also means a dangerous overdose of those other drugs.

At normal doses, DXM acts on the brain to suppress the cough reflex. At the much larger doses used recreationally, DXM and its metabolite (dextrorphan) block NMDA glutamate receptors — the same action behind the dissociative effects of ketamine and PCP — producing detachment, distorted perception, and hallucinations. DXM also affects serotonin and adrenaline systems, which is why high doses can raise blood pressure and heart rate and, especially when combined with other serotonergic drugs, can contribute to serotonin syndrome. Users describe dose-dependent 'plateaus,' with effects becoming more intense and dissociative as the dose increases.

At recommended doses, DXM relieves coughing with few side effects. Misused at high doses, effects are dose-dependent and can include euphoria and restlessness at lower recreational doses, progressing to exaggerated sensations, distorted vision, loss of coordination, and — at the highest doses — intense hallucinations, a sense of leaving the body, and near-total dissociation. Common unwanted effects include nausea and vomiting, dizziness, rapid heartbeat, sweating, high blood pressure, and impaired coordination and judgment.

DXM is dangerous in several ways when misused. High doses impair coordination and judgment, raising the risk of accidents, and can cause dangerously high blood pressure, rapid heart rate, and — at extreme doses — depressed breathing. The most underappreciated danger is combination products: many cough-and-cold medicines pair DXM with acetaminophen, antihistamines, or decongestants, so taking enough to feel DXM's effects can cause acetaminophen liver toxicity or antihistamine overdose at the same time. Mixing DXM with alcohol or other drugs, or with serotonergic medications (which raises the risk of life-threatening serotonin syndrome), is especially hazardous. Heavy, repeated use can lead to tolerance and dependence, and high doses can trigger psychosis. If an overdose is suspected, contact Poison Control at 1-800-222-1222, or call 911 in an emergency. For help with misuse, the SAMHSA helpline is 1-800-662-4357.