Rhabdomyolysis and cholestatic hepatitis under treatment with simvastatin and chlorzoxazone

Acute rhabdomyolysis under treatment with HMG-CoA reductase inhibitors ("st atins") is a group-specific if rare side effect. Muscle toxicity of statins can be potentiated by medication influencing their metabolism. Here drug i nteractions on the level of the microsomal cytochrome P450 enzymes play an important role. We report the first case of marked rhabdomyolysis with cholestatic hepatiti s in a 73-year-old woman treated with simvastatin and chlorzoxazone. Withdr awal of the causal medication and conservative therapy with volume substitu tion and forced diuresis was followed by almost complete resolution of the symptoms with normalisation of the blood tests. Possible mechanisms involve d in the drug interactions are discussed. Thorough knowledge of the enzyme systems involved in drug metabolism. helps to predict possible adverse drug interactions and prevent toxic effects.