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Gliclazide and clarithromycin — GPhC CRA MCQ

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HardDrug InteractionsGliclazide and clarithromycinGPhC CRA

A 57-year-old man with type 2 diabetes is prescribed gliclazide 80 mg twice daily. He starts clarithromycin for pneumonia and reports sweating and confusion before lunch; capillary glucose is 2.8 mmol/L. What is the most important interaction to flag?

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Correct answer: A — Clarithromycin can increase sulfonylurea-associated hypoglycaemia

Macrolides can increase the hypoglycaemic effect of sulfonylureas in susceptible patients. The documented low glucose with symptoms makes this clinically urgent. The pharmacist should ensure hypoglycaemia is treated, advise monitoring and contact the prescriber about antibiotic or diabetes-medicine adjustment.

Reference: BNF