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Sulfonylurea and co-trimoxazole — GPhC CRA MCQ

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HardEndocrine TherapeuticsSulfonylurea and co-trimoxazoleGPhC CRA

A 64-year-old man with type 2 diabetes is prescribed gliclazide 80mg twice daily. He starts co-trimoxazole for prostatitis and reports sweating and confusion before lunch. Capillary glucose is 2.9mmol/L. What is the most important interaction to flag?

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Correct answer: E — Co-trimoxazole can increase sulfonylurea effect and hypoglycaemia risk

Co-trimoxazole can increase the hypoglycaemic effect of sulfonylureas such as gliclazide. The patient's symptoms and glucose reading confirm clinically important hypoglycaemia. The prescriber should review antibiotic choice and diabetes management, and the patient needs hypoglycaemia treatment and safety advice. The interaction is not treatment failure of the antibiotic.

Reference: BNF