Combination drug products: an indication for medication reconciliation and pharmacist counseling

To describe a case of drug-induced rhabdomyolysis that occurred because of an inadvertent duplication in statin therapy.

Tertiary care academic teaching hospital in Oklahoma, December 2005.

A 45-year-old white man received the combination therapy simvastatin 80 mg/ezetimibe 10 mg (Vytorin-Merck/Schering-Plough) daily after a coronary artery bypass graft (CABG) procedure. This patient was also receiving simvastatin 80 mg daily and cyclosporine 150 mg twice daily, which had been prescribed before CABG. The use of two simvastatin products prescribed at high doses subsequently led to rhabdomyolysis and renal failure.

Statin therapy was discontinued at admission, and the patient was aggressively hydrated with 0.45% sodium chloride injection containing 50 mEq of sodium bicarbonate per liter at a rate of 250 mL/hour to alkalinize his urine. Hydration therapy alone decreased the patient's serum creatine kinase level to 910 units/L by day 7, but his serum creatinine remained elevated at 2.7 mg/dL. To manage rhabdomyolysis during hospitalization, the patient received a total of 6.7 liters of 0.45% sodium chloride injection with 50 mEq of sodium bicarbonate per liter. The patient was discharged 7 days after admission to a rehabilitation facility for continued strengthening of muscle tissue.

The increased use of combination drug products poses an increased risk of therapeutic duplication in patients. The medication reconciliation process and proper counseling by pharmacists is necessary to avoid these potentially harmful errors.