Rhabdomyolysis after ezetimibe/simvastatin therapy in an HIV-infected patient

A 42-year-old white man was admitted to hospital with a 3-day history of progressive muscle weakness, myalgias and dark urines. He was HIV/hepatitis C virus (HCV) coinfected, with an absolute CD4+ T lymphocyte count of 393 cells/mm3, a serum HIV-1 RNA load of <40 copies/mm3 and an HCV RNA load of 6 log10 before admission to the hospital. His antiretroviral treatment consisted of lamivudine (150 mg bd), abacavir (300 mg bd), indinavir (400 mg bd) and ritonavir (100 mg bd) at the time of admission. This regimen had not been changed in the past 2 years. The patient also had a history of hyperlipidaemia, coronary artery disease and a cerebral stroke in 2004. Because of severe hyperlipidaemia (LDL cholesterol, 175 mg/dL; triglyceride level, 191 mg/dL) that was refractory to dietary therapy and a 6-month trial of pravastatin (40 mg/day), a combination of ezetimibe (10 mg/day) and simvastatin (40 mg/day) was introduced 3 weeks prior to admission. The patient was also taking aspirin (75 mg/day), bisoprolol (5 mg/day) and perindopril (2 mg/day). He took no herbal or over-the-counter medications, and he did not use alcohol or illicit drugs. His basal serum creatinine level was 65 μmol/L (0.81 mg/dL). Calculated creatinine clearance using the modified diet in renal disease formula (MDRD) was 98 mL/min. Ten days after the initiation of treatment with ezetimibe– simvastatin combination, the patient noted the development of new generalized and progressive muscle weakness and dark urines. He denied having recently exercised strenuously or having sustained a trauma, and he had no prior history of HIV myopathy. He was well nourished (weight 66 kg). Laboratory evaluation revealed findings that were consistent with rhabdomyolysis [creatine kinase (CK),