dextromethorphan + caffeine

Dextromethorphan + caffeine is a combination of two active ingredients: dextromethorphan, a non-opioid antitussive, and caffeine, a methylxanthine stimulant. **Dextromethorphan** is primarily used as a cough suppressant that works by decreasing activity in the part of the brain that causes coughing. It is the dextro-rotatory isomer of the synthetic opioid levorphanol but does not exhibit typical opioid characteristics except for its antitussive property. **Caffeine** is a central nervous system stimulant that is found in many over-the-counter products including energy supplements, pain relief products, and cough and cold combinations. When used together, caffeine at high concentrations can significantly inhibit the metabolism of dextromethorphan by inhibiting its conversion to dextrorphan, potentially leading to prolonged and enhanced effects. This interaction occurs because caffeine affects the cytochrome P450 enzymes involved in dextromethorphan metabolism. The combination has legitimate therapeutic uses but has also been subject to misuse, particularly when combined with other substances or taken in excessive amounts.