Coadministration of atazanavir/ritonavir (300/100 mg once daily) and daclatasvir (20 mg once daily) increased daclatasvir AUC, Cmax and Cmin by 110%, 35% and 265%, respectively (results dose-normalised to 60 mg dose). The dose of daclatasvir should be reduced to 30 mg once daily when coadministered with atazanavir/ritonavir or other strong inhibitors of CYP3A4.

No dosage adjustment for daclatasvir is necessary with moderate CYP3A inhibitors, including atazanavir (unboosted).

Coadministration of atazanavir/ritonavir (300/100 mg, once daily) and daclatasvir (60 mg once daily alone or 20 mg once daily with atazanavir/ritonavir) was studied 14 healthy subjects. Dose normalised (to 60 mg) daclatasvir Cmax, AUC and C24 increased 35%, 110% and 265%, respectively. Daclatasvir AUC and C24 for a 30 mg dose were projected to increase by 5% and 83%, while Cmax was projected to decrease by 32%. These data support a dose reduction to 30 mg daclatasvir daily, when given in combination with atazanavir/ritonavir 300/100 mg daily.