An update on the toxicological considerations for protease inhibitors used for hepatitis C infection.

Hepatitis C virus protease inhibitors (PIs) are important components of many direct acting antiviral regimens. Many clinical trials and real-world studies have described the safety data for individual PIs. We aimed to review the safety of both the first and second generation PIs in patients with chronic hepatitis C (CHC). Areas covered: The unique pharmacokinetic properties of PIs partly explain their toxicities. Second generation PIs, when used without interferon and ribavirin, are well-tolerated. Use of PIs in renal impaired patients or those on dialysis appears to be safe. Decompensated cirrhosis is a contraindication for PIs use due to increased drug exposure and risk of liver decompensation. Drug-drug interactions are common and should be always monitored; some drugs should not be co-administered with PIs. In patients with co-infected hepatitis B virus, reactivation after DAA (whether PI-containing or not) is a concern. Expert opinion: Second generation PIs are key players in the current DAA era. Post-marketing surveillance is essential to monitor unknown adverse events and drug-drug interactions. Non-PI based DAA should be used in decompensated liver disease. The use of these drugs should also be explored in the paediatric population.