Pharmacokinetics of new oral hepatitis C antiviral drugs.

Introduction: Approximately 175 million people worldwide are chronically infected with the hepatitis C virus (HCV), representing 3% of the total world population. Until recently, the only available therapeutic option for these patients was the combination of pegylated IFN-alpha plus ribavirin that overall resulted in HCV eradication in less than a half of cases. The development of new therapies with greater efficacy has been eagerly awaited but new challenges have emerged, with drug interactions being among the most challenging. Areas covered: This review updates the main pharmacokinetic and pharmacodynamic characteristics of the most promising new oral direct-acting antivirals (DAA) for hepatitis C. Given that a large proportion of chronic hepatitis C patients receive other medications, drug interactions are further discussed. Expert opinion: The recent approval of the first HCV genotype 1 protease inhibitors is a landmark step in the fight against the HCV pandemic. The benefit of higher rates of response along with shorter duration of treatment is counterbalanced by significant drug interactions and unprecedented complexities in the use of these drugs and management of their side effects. The knowledge of key pharmacologic parameters of distinct DAA is important for care providers in charge of chronic hepatitis C patients as it will avoid the danger of unexpected drug interactions. This concern must be particularly emphasized in special group populations, such as in HIV-HCV coinfected individuals and transplant patients, in whom interactions between DAA and antiretrovirals or immunosuppressants, respectively, are frequent.