Guaifenesin-DM

**Semantic type:** Pharmacologic Substance

**Definition:** A combination preparation containing guaifenesin and the opioid agonist dextrometorphan with expectorant and antitussive activities, respectively. Guaifenesin works by drawing water into respiratory tracts, by which reducing adhesiveness and surface tension of mucus as well as increasing hydration of mucus, thereby reducing the viscosity of mucus and making cough more productive. Dextrometorphan, a synthetic, methylated dextrorotary analogue of levorphanol, exhibits antitussive activity by activating opioid receptors in the cough center in the central nervous system, thereby raising the threshold for coughing.

**Synonyms:** - Guaifenesin-Dextromethorphan - Robitussin DM