HIV and TB coinfection is a widespread problem, especially in resource-limited settings. Interactions between drugs metabolized through cytochrome P450 enzymes and p-glycoprotein efflux pump, such as rifampin and HIV protease inhibitors, complicate the management of both pathologies when they coexist. The article by Decloedt et al. elegantly assesses the pharmacokinetics of three twice-daily escalating doses of lopinavir/ritonavir (400/100 mg, 600/150 mg and 800/200 mg), together with 600 mg daily of rifampin in 21 black African HIV-infected patients without TB. The article also reports safety, tolerability and virological outcomes after 3 weeks. Doubling lopinavir/ritonavir dose overcomes rifampin induction effect with good tolerability. However, concerns arise regarding the real interactions, tolerability and virological efficacy in HIV-TB-coinfected patients, which may differ from healthy volunteers or HIV-infected patients without TB. © 2011 Expert Reviews Ltd.