Toxicity and risks from drug-to-drug interactions of new antivirals for chronic hepatitis C.

The new direct acting antivirals (DAAs), defined as those drugs that are effective in combinations without interferon, have totally changed HCV treatment and probably in few years will also totally change global landscape of advanced liver diseases. The advantage of DAAs is a low-risk/high-benefit ratio. Although overall adverse events during DAAs treatment are limited in frequency and severity, some toxicity issues emerged during the first years of real-life experience with these drugs. Another peculiar characteristic of present DAAs is a high probability of interaction with other "common-use" drugs, such as anti-hypertensive, anti-platelet, antiarrhythmic and cholesterol lowering agents. Above all, special attention should be paid in older patients and in those belonging to special populations, who more frequently require the concomitant use of polytherapy.