What is known and objective: Limited data are available on co-administration of acenocoumarol with direct-acting antiviral agents for chronic hepatitis C virus infection.
Case summary: We report a case of a patient who required a significant increase in acenocoumarol weekly dose probably due to an interaction with ombitasvir/paritaprevir/ritonavir and/or dasabuvir. A causality assessment of the drug-drug interaction leading to a reduced INR was conducted according to the Naranjo algorithm. A score of 6 suggested that the adverse drug reaction was probable.
What is new and conclusion: Because of possible INR abnormalities during the concomitant use of acenocoumarol, ombitasvir/paritaprevir/ritonavir and dasabuvir, clinicians should closely monitor INR values.
Keywords: acenocoumarol; antiviral agents; drug interactions; hepatitis C.
© 2016 John Wiley & Sons Ltd.