Coadministration of atazanavir/cobicistat (300/150 mg once daily) and atorvastatin (10 mg) increased atorvastatin AUC and Cmax by 822% and 1785% due to inhibition of CYP3A, OATP1B1 and BCRP by atazanavir/cobicistat. There was no effect of atorvastatin on atazanavir/cobicistat exposure. Coadministration is not recommended. If the use of atorvastatin is considered strictly necessary, the lowest possible dose of atorvastatin should be used and the daily dose should not exceed 10 mg with careful monitoring.