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Colchicine toxicity interaction — GPhC CRA MCQ

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HardMusculoskeletal TherapeuticsColchicine toxicity interactionGPhC CRA

A 70-year-old man with CKD stage 3b is taking colchicine 500 micrograms twice daily for gout. He is prescribed clarithromycin for a chest infection. He has abdominal pain and muscle weakness after two doses of clarithromycin. What is the most important interaction to flag?

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Correct answer: A — refer urgently and contact the prescriber because colchicine toxicity is possible

Clarithromycin can increase colchicine exposure through CYP3A4 and P-glycoprotein inhibition. Renal impairment further increases the risk of serious colchicine toxicity, which may present with gastrointestinal symptoms and myopathy. Urgent medical assessment and prescriber contact are needed. Continuing the combination could be dangerous.

Reference: BNF