Clarithromycin and other antimicrobial agents in the treatment of disseminated Mycobacterium avium infections in patients with acquired immunodeficiency syndrome.

Disseminated infection with Mycobacterium avium is common with late-stage acquired immunodeficiency syndrome (AIDS), and no antimicrobial agent has been found to be clearly effective. A multicenter open trial was conducted to assess the antimicrobial activity and clinical efficacy of clarithromycin--a new macrolide antibiotic--against disseminated M avium in 77 patients with late-stage AIDS. Blood cultures were taken at baseline and during treatment; side effects were also evaluated. Mycobacterium avium was eradicated from blood cultures in 11 (63%) of 16 evaluable patients receiving daily doses or 500 or 1000 mg, (n = 21) and in 45 of 46 (98%) of those receiving 1500 or 2000 mg (n = 56). Eradication after 2 months was influenced by continuity of drug treatment; 36 of 42 patients with no relapse had received continuous treatment vs six of 14 patients whose drug treatment had been stopped for 7 days or longer. After 2 to 7 months of treatment, acquired resistance associated with relapse was observed. Drug side effects were elevated liver enzyme levels (26%) and impaired hearing (4%). Concomitant AIDS drugs had no favorable effect on outcome and may have worsened liver toxicity. Clarithromycin has bacteriologic efficacy against M avium infection in late-stage AIDS, although drug resistance eventually develops. Further studies are needed to investigate safe, effective concomitant drugs.