Co-administration is not recommended. The interaction has not been studied with any of the components of Biktarvy. Co-administration of rifapentine may decrease bictegravir and tenofovir alafenamide plasma concentrations (due to induction of CYP3A and P-gp).

Coadministration may decrease concentrations of bictegravir and tenofovir alafenamide. Coadministration with rifapentine is not recommended. Coadministration of rifampin (600 mg once daily) and bictegravir (75 mg single dose) decreased bictegravir Cmax and AUC by 28% and 75%.

The effect of daily rifapentine (600 mg) plus isoniazid (300 mg) (1HP) on bictegravir trough concentration and virologic response was evaluated in people living with HIV with latent TB infection. Bictegravir trough concentrations after 1HP initiation were determined in 48 study participants. The percentage of bictegravir trough concentrations above the protein adjusted EC95 (162 ng/mL) were 65% on day 15 and 35% on day 29 post 1HP initiation. Viral loads were below 200 and 50 copies/mL in 100% and 98% of the enrolled participants before initiation of 1HP; 92% and 73% on day 15; 98% and 92% on day 29 and 100% and 98% 3 months after 1HP discontinuation. Bictegravir concentrations were significantly decreased with the concurrent use of 1HP therefore coadministration is not recommended.