Dextromethorphan: Indications Dextromethorphan is a powerful antitussive agent that is suitable for dry cough. If one keeps in mind that this substance is prescription-free on a worldwide scale, one must be amazed by the relative lack of documentation available on the drug. Only in a few, small studies has dextromethorphan been compared directly to codeine. A similar antitussive activity was thereby established for both substances. Comparative doses of dextromethorphan may be better tolerated, but the efficacy of codeine is normally more reliable. According to some studies, there is no connexion between the plasma levels (of the metabolite dextrorphan) and the cough suppressant action. Literature yields contradictory data on the onset and peak stages of efficacy. Dextromethorphan is a constituent of numerous cough medicine combinations. Most of these combinations have an irrational character; adequate comparisons with dextromethorphan as a single substance are not available. Copyright © 1996 Infomed-Verlags AG