Reduced blood levels w/ Mg- or Al-containing antacid, Fe & Ca supplements, multivitamins & inducing agents, etravirine (w/o boosted PIs), tipranavir/ritonavir, rifampicin, St. John's wort, & certain antiepileptic medicines. May decrease plasma conc & reduce therapeutic effect w/ UGT1A3, UGT1A9, CYP3A4, P-gp, & BCRP enzyme inducers. May increase plasma conc w/ UGT1A3, UGT1A9, CYP3A4, P-gp, & BCRP enzyme inhibitors. Increased metformin conc. May increase plasma conc of medicines whose excretion involves organic cation transporter 2 (OCT2) & multidrug & toxin extrusion transporter 1 (MATE-1) (eg, dofetilide, metformin) or dependent upon organic anion transporters 3.