*daclatasvir is a drug for the treatment of hepatitis c (hcv).*daclatasvir inhibits the hcv nonstructural protein ns5a. recent research suggests that it targets two steps of the viral replication process, enabling rapid decline of hcv rna.*daclatasvir has been tested in combination regimens with pegylated interferon and ribavirin, as well as with other direct-acting antiviral agents including asunaprevir and sofosbuvir.