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PDE5 inhibitor and nitrate — GPhC CRA MCQ

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ModerateDrug InteractionsPDE5 inhibitor and nitrateGPhC CRA

A man taking sildenafil 50 mg for erectile dysfunction is newly prescribed isosorbide mononitrate MR 30 mg daily after angina review. He says he uses sildenafil most weekends. What is the most important interaction to flag?

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Correct answer: B — Sildenafil with nitrates can cause severe hypotension

Phosphodiesterase type 5 inhibitors and nitrates together can cause profound hypotension. The issue is clinically important because the patient uses sildenafil regularly. The pharmacist should not supply without prescriber clarification and should counsel the patient clearly on the risk.

Reference: https://www.pharmacyregulation.org/registration-assessment#stage-8-order-94