Coadministration has not been studied with doravirine or doravirine/lamivudine/tenofovir disoproxil but no effect on doravirine is expected. No dose adjustment is required.

The effect of ribavirin (800 mg/day) on the plasma and intracellular PK of zidovudine, lamivudine and stavudine was studied in HIV/HCV co-infected subjects receiving zidovudine plus lamivudine, or stavudine plus lamivudine. Plasma zidovudine, lamivudine and stavudine and intracellular drug and endogenous triphosphates were measured at baseline without ribavirin and after 8-12 weeks of ribavirin co-administration. Plasma results showed no impact of ribavirin on nucleoside concentrations and ribavirin levels were consistent with previous data measured in the absence of the three NRTIs. Similar findings were observed for the deoxycytidine and deoxythymidine triphosphate analogues, when given with or without ribavirin, suggesting that ribavirin does not perturb the intracellular metabolism of zidovudine, lamivudine or stavudine.