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Serotonin toxicity — GPhC CRA MCQ

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HardCNS TherapeuticsSerotonin toxicityGPhC CRA

A 44-year-old woman taking venlafaxine 225mg daily is prescribed tramadol for acute back pain. Two days later her partner reports agitation, sweating, diarrhoea and muscle twitching. Her temperature is 38.4C and pulse is 118bpm. What is the most important interaction to flag?

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Correct answer: C — refer urgently for suspected serotonin toxicity and stop further tramadol pending review

Venlafaxine with tramadol increases serotonergic activity and can precipitate serotonin toxicity. Agitation, sweating, diarrhoea, myoclonus, fever and tachycardia are concerning features requiring urgent assessment. Further tramadol should be withheld pending clinical review. Symptomatic OTC treatment would risk delaying care.

Reference: BNF