simvastatin and verapamil

MajorAvoid this combination where possible.

Mechanism

Verapamil inhibits CYP3A4, the hepatic enzyme responsible for metabolising simvastatin, leading to increased plasma concentrations of simvastatin.

What it means clinically

Elevated simvastatin levels increase the risk of dose-dependent myopathy and rhabdomyolysis, which can cause muscle pain, weakness, and potentially kidney damage.

What to do

Avoid co-prescribing verapamil with simvastatin doses above 10 mg daily. If combination is necessary, limit simvastatin to 10 mg/day and monitor for muscle symptoms and creatine kinase levels.

Evidence

Well-established through pharmacokinetic studies and case reports.

The two drugs

simvastatinHMG-CoA reductase inhibitorRead the monograph verapamilCalcium channel blocker (non-dihydropyridine)Read the monograph

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Other interactions involving simvastatin or verapamil

Educational reference for students and clinicians in training. It does not replace professional judgement, local protocols or current prescribing information.