Cases of Rhabdomyolysis Associated With High-Dose Simvastatin
Cases of Rhabdomyolysis Associated With High-Dose Simvastatin
Simvastatin is a hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor (statin) commonly used for the treatment of hypercholesterolemia. While it is a relatively safe drug when used for this indication, simvastatin and other HMG-CoA reductase inhibitors have been associated with rhabdomyolysis. This adverse effect can occur when simvastatin is used alone, but it is most commonly reported when simvastatin is given in combination with medications that inhibit cytochrome P-450 isoenzyme 3A4 (CYP3A4).
Rhabdomyolysis is characterized by a severe breakdown of skeletal muscle that results in the release of myoglobin into the blood. Myoglobin is a nephrotoxic substance that can lead to renal failure; therefore, rhabdomyolysis is a medical emergency. Patients often report muscle aches and pain, with the calves and lower back being the most commonly involved muscle groups. In addition, patients may report having tea or cola-colored urine, which results from the extensive buildup of myoglobin. This symptom is usually the one that first impels patients to seek medical attention.
We report two cases of rhabdomyolysis that were caused by the use of high-dose simvastatin in combination with nefazodone and azithromycin in one instance and gemfibrozil in the second.
Simvastatin is a hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor (statin) commonly used for the treatment of hypercholesterolemia. While it is a relatively safe drug when used for this indication, simvastatin and other HMG-CoA reductase inhibitors have been associated with rhabdomyolysis. This adverse effect can occur when simvastatin is used alone, but it is most commonly reported when simvastatin is given in combination with medications that inhibit cytochrome P-450 isoenzyme 3A4 (CYP3A4).
Rhabdomyolysis is characterized by a severe breakdown of skeletal muscle that results in the release of myoglobin into the blood. Myoglobin is a nephrotoxic substance that can lead to renal failure; therefore, rhabdomyolysis is a medical emergency. Patients often report muscle aches and pain, with the calves and lower back being the most commonly involved muscle groups. In addition, patients may report having tea or cola-colored urine, which results from the extensive buildup of myoglobin. This symptom is usually the one that first impels patients to seek medical attention.
We report two cases of rhabdomyolysis that were caused by the use of high-dose simvastatin in combination with nefazodone and azithromycin in one instance and gemfibrozil in the second.
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