Multiple drug interactions in a renal transplant patient leading to simvastatin-induced rhabdomyolysis: a case report.

Rhabdomyolysis, a syndrome characterized by muscle necrosis with release of toxic intracellular muscle constituents, can be a potentially fatal side effect of medical therapy. Here I report a patient with a 12-year history of simvastatin use who presented with rhabdomyolysis. He had a renal transplant and has been on a stable dose of cyclosporine for the past year. Recent medication changes were the addition of ranolazine, carvedilol, and diltiazem about two months prior to the episode of rhabdomyolysis. Discontinuation of the ranolazine, diltiazem, and simvastatin resulted in prompt resolution of the episode. It is suggested that these medications, acting in concert with cyclosporine, altered the metabolism of simvastatin, causing the episode of rhabdomyolysis. Clinicians should be alert to the possibility of multiple drug interactions causing rhabdomyolysis.