When doravirine is co-administered with rifabutin, the doravirine dose should be increased to 100 mg twice daily (the doses should be taken approximately 12 hours apart). Co-administration of rifabutin (300 mg once daily) and doravirine (100 mg single dose) decreased doravirine AUC, Cmax and C24 by 50%, 1% and 68%, respectively.

Co-administration of doravirine (100 mg single dose) with rifabutin (300 mg once daily) was studied in 12 subjects. Doravirine AUC, Cmax and C24 decreased by 50%, 1% and 68% respectively. If doravirine is co-administered with rifabutin, increase doravirine dosage to one tablet twice daily (approximately 12 hours apart) for the duration of rifabutin co-administration. At least a 4-week cessation period is recommended prior to initiation of doravirine.

Co-administration of doravirine (100 mg, single dose) with rifabutin (300 mg, once daily, for 16 days) was studied in 12 healthy male subjects. Doravirine AUC, Cmax and C24 decreased by 50%, 1% and 68%, respectively. Pharmacokinetic modelling projected that doravirine (100 mg twice daily) and rifabutin (300 mg once daily) would result in similar steady-state Ctrough values as those observed with doravirine 100 mg once daily without rifabutin. Doravirine may be coadministered with rifabutin when the doravirine dose frequency is increased from 100 mg once daily to 100 mg twice daily.