TABLE 2.

SUMMARY OF INTERACTIONS BETWEEN RIFAMYCINS AND ANTIRETROVIRALS

	Rifampin	Rifabutin
Cytochrome P450 interaction	+++	+
Interactions with PIs	++++, recommended for use only with  a regimen that includes two PIs	++, PIs boost Rif levels requiring reduction of dose
Interactions with NNRTIs	+, slightly decreases levels of efavirenz, but is favored regimen	++, decreased levels of Rif with efavirenz requiring increased Rif dose. Should not be used with delaviridine
Interactions with CCR-5 receptor antagonists	+	+
Interactions with integrase inhibitors	+	+
Cost and availability	++	++++, expensive and less available in resource-poor settings
Efficacy	++++	++++

Definition of abbreviations: NNRTIs = nonnucleoside reverse transcription inhibitors; PIs = protease inhibitors; Rif = Rifabutin.