Dextromethorphan contraindications

Contraindications Coadministration with monoamine oxidase inhibitors (MAOls), hypersensitivity to dextromethorphan or its components... 

Two fatal cases of hyperpyrexia and coma (symptoms similar to the serotonin syndrome) have occurred in patients taking phenelzine with dextromethorphan (in overdosage in one case). Three other serious but non-fatal reactions occurred in patients taking dextromethorphan with isocarboxazid or phenelzine. MAOIs should not be used with dextromethorphan. Mo-clobemide inhibits the metabolism of dextromethorphan, and isolated cases of severe CNS reactions have occurred with the combination, which is also contraindicated. 

Despite the very limited information available, the severity of the reactions indicates that patients taking MAOIs should avoid taking dextromethorphan. The manufacturer of moclobemide also contraindicates the concurrent use of dextromethorphan. Patients should be warned that many cough preparations contain dextromethorphan. 

Dextromethorphan is contraindicated in patients taking selective serotonin reuptake inhibitors and monoamine oxidase inhibitors. 

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