Rifabutin therapy for disseminated Mycobacterium avium complex infection.

Although numerous antimicrobial agents have been used to treat disseminated Mycobacterium avium complex (MAC) infection, the optimal therapy for this disease is unknown. One potentially effective agent is rifabutin, which has demonstrated activity against MAC both in vitro and in animal models of infection. In clinical trials, cultures of blood from 46% to 92% of patients become sterile after therapy with rifabutin combined with ethambutol, clofazimine, or amikacin. Moreover, the efficacy of ethambutol combined with clofazimine is markedly enhanced by rifabutin. In combination with clarithromycin, rifabutin at dosages of > or = 450 mg/d has been associated with a high incidence of uveitis, thus indicating that only 300 mg/d may be given with this macrolide. Although a definitive role for rifabutin in the treatment of MAC infection has not been established, this agent will likely be of value as an adjunct to macrolide-based therapy or in the treatment of macrolide-intolerant patients.