Drug Interaction Report

MONITOR: Coadministration with cobicistat may increase the plasma concentrations of rosuvastatin. The proposed mechanism is cobicistat inhibition of the OATP1B1-mediated hepatic uptake of rosuvastatin. In 10 healthy volunteers, administration of a single 10 mg dose of rosuvastatin in combination with a 150 mg dose each of cobicistat and elvitegravir increased mean rosuvastatin peak plasma concentration (Cmax) and systemic exposure (AUC) by 89% and 38%, respectively. High levels of HMG-CoA reductase inhibitory activity in plasma is associated with an increased risk of musculoskeletal toxicity. Myopathy manifested as muscle pain and/or weakness associated with grossly elevated creatine kinase exceeding ten times the upper limit of normal has been reported occasionally. Rhabdomyolysis has also occurred rarely, which may be accompanied by acute renal failure secondary to myoglobinuria and may result in death.

MANAGEMENT: Caution is advised if rosuvastatin is prescribed with cobicistat. The lowest starting dosage of rosuvastatin is recommended, then titrated as needed based on clinical response and tolerance. According to some authorities, the dose of rosuvastatin should not exceed 10 mg daily. All patients receiving statin therapy should be advised to promptly report any unexplained muscle pain, tenderness or weakness, particularly if accompanied by fever, malaise and/or dark colored urine. Therapy should be discontinued if creatine kinase is markedly elevated in the absence of strenuous exercise or if myopathy is otherwise suspected or diagnosed.