Dextromethorphan

Dextromethorphan is an over-the-counter drug that is sold alone and in combination with other products as a cough suppressant for children and adults. We have previously recommended dextromethorphan as a safe and effective cough suppressant for both children and adults. However, the weight of the evidence now suggests that dextromethorphan is no more effective than an inactive placebo syrup in suppressing a nighttime cough in children. It is the disomer of the potent opiate analgesic 3-methoxyN-methylmorphine (levorphanol). Although dextromethorphan is structurally related to opioids, it is devoid of analgesic or sedative effects at therapeutic doses. Dextromethorphan is metabolized by CYP2D6 to a more potent metabolite, dextrorphan. Dextrorphan is a stronger noncompetitive antagonist than dextromethorphan for the N-methyl-D-aspartate (NMDA) glutamate receptor.These properties promote its use in treatment of neuropathic and postoperative pain management.