Washington, DC- Patients who take more than 20 mg/day of simvastatin in addition to amiodarone are at increased risk of rhabdomyolysis, the Food and Drug Administration has reminded physicians in the US [1].

The statin drug is available on its own as Zocor (Merck) and in generic forms, and also paired with ezetimibe (Vytorin, Merck & Schering-Plough) and extended-release niacin (Simcor, Abbott). The widely used antiarrhythmic amiodarone is available as generics and under various trade names such as Cordarone (Wyeth-Ayerst Laboratories) and Pacerone (Upsher-Smith Laboratories).

Although rhabdomyolysis is considered a classwide possible adverse effect of statin therapy, it received special consideration in 2002 when the FDA revised the simvastatin labeling to warn that it can occur when the drug is given at >20 mg/day in patients also taking amiodarone.

"However, the FDA continues to receive reports of rhabdomyolysis in patients treated concurrently with amiodarone and simvastatin, particularly with simvastatin doses greater than 20 mg daily," the agency said in its alert to physicians.

Prescribers should be aware of this increased risk, it said, "and they should avoid doses of simvastatin greater than 20 mg per day in patients taking amiodarone."