Drug Interaction Report

GENERALLY AVOID: Coadministration with drugs that are combined P-glycoprotein (P-gp) and moderate inducers of CYP450 3A4 or sole moderate inducers of CYP450 3A4 may decrease the plasma concentrations of lenacapavir and result in a potential loss of virologic response. The proposed mechanism is increased clearance due to induction of the isoenzyme CYP450 3A4, which is partly responsible for the metabolism of lenacapavir and induction of the P-gp transporter of which lenacapavir is a substrate. In pharmacokinetic studies conducted in fasted subjects without HIV, coadministration of a single oral dose of lenacapavir 300 mg with the combined P-gp and moderate inducer of CYP450 3A4 efavirenz 600 mg once daily decreased the systemic exposure (AUC) and peak plasma concentration (Cmax) of lenacapavir by approximately 56% and 36%, respectively.

MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiviral drug levels, concomitant use of lenacapavir with drugs that are combined P-gp and moderate inducers of CYP450 3A4 or sole moderate inducers of CYP450 3A4 should generally be avoided.

ADJUST DOSING INTERVAL: Food does not appear to substantially alter the pharmacokinetics of tipranavir. When tipranavir capsules or oral solution was coadministered with ritonavir capsules at steady-state, no clinically significant changes in tipranavir peak plasma concentration (Cmax) and systemic exposure (AUC) were observed under fed conditions (500 to 682 kcal, 23% to 25% calories from fat) relative to fasted conditions. The effect of food on tipranavir exposure during coadministration with ritonavir tablets has not been evaluated. High-fat foods may enhance the gastrointestinal absorption of tipranavir. In a multiple-dose study, administration of tipranavir capsules with a high-fat meal (868 kcal, 53% from fat, 31% from carbohydrates) increased the oral bioavailability of tipranavir by 31% compared to administration with toast and skimmed milk, but did not significantly affect tipranavir Cmax. Thus, tipranavir may be safely taken with standard or high-fat meals.

MANAGEMENT: Tipranavir coadministered with low-dose ritonavir should be taken with food to improve the gastrointestinal tolerability of ritonavir. According to the product labeling, tipranavir coadministered with ritonavir capsules or solution can be taken with or without meals, whereas tipranavir coadministered with ritonavir tablets must be taken with meals.