The FDA has issued a warning regarding an increased risk of rhabdomyolysis when simvastatin is used with amiodarone. The risk is dose-related and increases when simvastatin ≥20mg/day is dosed with amiodarone. This warning includes simvastatin-containing products such as Simcor (niacin extended-release/simvastatin, from Abbott) and Vytorin (simvastatin/ezetimibe, from Merck/Schering-Plough).

Patients starting or increasing their dose of simvastatin while taking amiodarone should be advised of the risk of rhabdomyolysis and told to report any unexplained muscle pain, tenderness, or weakness immediately.

Simvastatin, an HMG-CoA reductase inhibitor, is indicated to treat a number of conditions including hypercholesterolemia, hypertriglyceridemia, and dyslipidemia. Amiodarone, a class III antiarrhythmic, is indicated for the treatment of documented, life-threatening recurrent refractory ventricular fibrillation or hemodynamically unstable ventricular tachycardia.

For more information visit www.fda.gov/medwatch/safety/2008/safety08.htm#Simvastatin.