Based on the results of drug interaction trials, no clinically relevant changes in exposure were observed for tenofovir with concomitant use of daclatasvir. Coadministration of tenofovir-DF (300 mg, once daily) with daclatasvir (60 mg, once daily) increased daclatasvir Cmax, AUC, and Cmin by 6%, 10%, 15%, respectively. No clinically relevant changes in daclatasvir exposure were observed with tenofovir. Daclatasvir, in vitro, did not inhibit OCT2 and did not have a clinically relevant effect on the pharmacokinetics of tenofovir, an OAT substrate.

This interaction has not been studied but is expected to increase daclatasvir concentrations due to CYP3A4 inhibition by cobicistat. The dose of daclatasvir should be reduced to 30 mg once daily when coadministered with cobicistat or other strong inhibitors of CYP3A4. Coadministration of tenofovir (300 mg once daily) and daclatasvir (60 mg once daily) had no clinically relevant effect on daclatasvir AUC, Cmax or Cmin (increases of 10%, 6% and 15%, respectively). There was no clinically relevant effect on tenofovir AUC (10% increase), Cmax (5% decrease) or Cmin (17% increase). No dose adjustment of daclatasvir or tenofovir is required. No clinically relevant effect is expected on concentrations of lamivudine.