Coadministration of darunavir/cobicistat (800/150 mg once daily) and atorvastatin (10 mg) increased atorvastatin AUC and Cmax by 290% and 319% due to inhibition of CYP3A4, OATP1B1 and BCRP by darunavir/cobicistat. However, atorvastatin did not affect darunavir/cobicistat exposure. When administration of atorvastatin and darunavir/cobicistat is required, it is recommended to initiate atorvastatin with the lowest dose, and titrate to desired response while monitoring for safety. A daily dose of 40 mg atorvastatin should not be exceeded with careful safety monitoring. (Note, the US product label for Prezcobix states not to exceed atorvastatin 20 mg/day.) In addition, caution is recommended in elderly individuals as they may be more susceptible to developing statin related adverse effects.

Coadministration has not been studied. Atorvastatin is metabolised mainly by CYP3A4. Based on drug-drug interaction studies with other NNRTIs and considering that nevirapine is a weak CYP3A4 inducer, coadministration is predicted to minimally impact atorvastatin exposure. No a priori dosage adjustment of atorvastatin is needed due to coadministration with nevirapine. However, treatment with statins requires periodic monitoring of lipid values and the atorvastatin dose should be adjusted based on the clinical response.