Dextromethorphan chemical properties

The biological consequences of molecular shape can be dramatic. Look at the structures of dextromethorphan and levomethorphan, for instance. (The Latin prefixes dextro- and levo- mean "right" and "left," respectively.) Dextromethorphan is a common cough suppressant found in many over-the-counter cold medicines, but its mirror-image, levomethorphan, is a powerful narcotic pain-reliever similar in its effects to morphine. The two substances are chemically identical except for their shapes, yet their biological properties are completely different. 

Dextromethorphan (d-3-methoxy-N-methylmor-phinan), a chemical relative of levomethorphan, was developed by modifying levomethorphan. However, unlike levomethorphan, dextromethorphan officially has no addictive or analgesic properties. 

While it is true that dextromethorphan is not technically a member of the opiate family, it is distantly related in its chemical composition. Dextromethorphan is created by from levomethorphan, which is classified as an opioid, the synthetic or semi-synthetic relatives of the natural chemical family called the opiates. Levomethorphan has most of the same qualities of all drugs in the opiate and opioid classes. This includes strong suppressive effects on the respiratory system. It is these strong effects on the respiratory system that make dextromethorphan an effective anti-cough agent. Opiate and opioid compounds have anti-cough properties but produce greater overall respiratory depression than dextromethorphan. 

Dextromethorphan, a simplified codeine, is a much-prescribed cough suppressant, with neither analgesic nor addictive properties. Chemically, it is ( + )-3-methoxy-iV-methylmorphinan. Ijts laevo stereoisomer has the analgesic and euphoric properties of morphine and (although not used in medicine) stands at the end of a line of work initiated by Grewe (1947) who was the first to show that the morphinan series can produce strong analgesics. 

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