Statins are widely prescribed to organ transplant recipients with hyperlipidemia. We report the case of a cardiac transplant recipient who developed severe rhabdomyolysis and acute renal failure after being switched from pravastatin to simvastatin. The patient's other medications included cyclosporin A and diltiazem. Unlike pravastatin, the metabolism and tissue concentrations of simvastatin--and of other statins - can be greatly affected by these drugs. The propensity of the individual statins to interact with drugs commonly prescribed to transplant recipients is reviewed.