Coadministration has not been studied. Bisoprolol is metabolised via CYP3A4 and 2D6 and a clinically significant interaction is unlikely as sofosbuvir does not affect CYP enzymes. Sofosbuvir is a prodrug and formation of its active metabolite is unlikely to be affected by comedications. [Note, the European SmPC recommends a maximum of 10 mg in severe hepatic impairment; the US Prescribing Information recommends an initial 2.5 mg in hepatic impairment with caution in further dose titration.]

Coadministration has not been studied but a clinically significant interaction is unlikely. Rifaximin is mainly excreted in faeces, almost entirely as unchanged drug. Rifaximin is an inducer of CYP3A4 and a substrate and inhibitor of P-gp. Although both drugs are substrates of P-gp, no effect on sofosbuvir concentrations is expected.