<p>Reduced therapeutic effect with drugs that are potent P-gp inducers in the intestine (eg rifampicin, St. John&#39;s wort, carbamazepine &amp; phenytoin), modafinil, phenobarb/ oxcarbazepine, rifabutin/ rifapentine. P-gp &amp;/or BCRP inhibitors. May result in serious symptomatic bradycardia when co-administered with amiodarone in combination with another direct acting antiviral.</p>