Dextromethorphan: Contraindications Advanced respiratory insufficiency, advanced hepatic disease.   Dextromethorphan: Cautions One should generally forgo an antitussive therapy if there is productive cough. It is better to use dextromethorphan as a mono-substance than in a (often irrational) cough medicine combination. Even though it is not a "real" opioid, intoxications can often be treated with naloxone. Copyright © 1996 Infomed-Verlags AG