Which of the following is not true for rifabutin as compared to rifampicin?
(A) Rifabutin has the longer half-life than rifampicin (B) Rifabutin has lesser incidence of drug-interactions (C) Rifabutin is more efficacious against MAC as compared to rifampicin (D) Rifabutin is more efficacious for pulmonary TB as compared to rifampicin
(D) Ans: D. Rifabutin is more efficacious for pulmonary TB as compared to rifampicin(Ref Goodman Gilman 12/e p1550, 1552, 1554, 1568; Katzung 12/e p845)Rifabutin:Stronger activity against Mycobacterium avium complex (compared to rifampicin).Ineffective against Mycobacterium tuberculosis. RifabutinRifampicin (Rifampin)RifapentineProtein binding 718597Oral 2068deg-tmax (hours)2.5-4.01.5-2.05.0-6.0degHalf-life (hours)32-67deg2-5deg14-18Intracellular/extracellular9524-60degAutoinduction40%deg38%20%CYP3A inductionWeakPronouncedModerateCYP3A substrateYesdegNoNo