Combined Use of Clarithromycin and Antimycobacterial Agents in Mycobacterium avium Complex Chronic Pulmonary Infection

Clarithromycin, a new macrolide antibacterial agent, is effective against disseminated Mycobacterium avium complex (MAC) infection in AIDS patients. In this study, we evaluated the therapeutic effect of clarithromycin, used in combination with other antimycobacterial drugs, against chronic pulmonary MAC infections in non-AIDS patients. Patients were divided into two groups based on the antimycobacterial drugs used for treatment. Patients of group A (n=5) were recent cases diagnosed to have atypical mycobacteriosis. They were treated on diagnosis, with rifampicin (450 mg q.d.), isoniazid (400 mg q.d.), and clarithromycin (200 mg b.i.d.). Patients of group B (n=23) were treated by adding clarithromycin (200 mg b.i.d.) to an existing therapeutic regimen consisting of several antimycobacterial agents. Clinical improvement was observed in seven (25%) patients, including two (40%) from group A and five (22%) from group B. Treatment was associated with a total mycobacterial eradication rate of 100% (5/5) in group A and 22% (5/23) in group B. Clarithromycin was more effective in patients receiving the drug as the first-line therapy than when used in later therapy. Clarithromycin had a lower efficacy rate in this study compared with the reported effect of clarithromycin in AIDS patients with in disseminated MAC infection. Our results of the first-line use of clarithromycin in combination with other mycobacterial agents for the treatment of chronic pulmonary MAC infections indicate that this agent has a limited but encouraging effect on atypical pulmonary mycobacteriosis.