Tuberculosis chemoprophylaxis using a liquid isoniazid-methadone admixture for drug users in methadone maintenance.

BACKGROUND Tuberculosis is common in drug users, although compliance with therapy may be difficult in this population. OBJECTIVE To evaluate an approach to enhancing compliance with tuberculosis chemoprophylaxis in drug users enrolled on methadone maintenance utilizing an isoniazid (INH)-methadone admixture. DESIGN A prospective cohort study. SETTING A drug treatment program in New Haven, Connecticut, USA. PATIENTS Opioid-dependent drug users enrolled in methadone maintenance. INTERVENTION Liquid isoniazid was mixed into subjects' daily dose of methadone. Vitamin B6 was given to subjects for self-administration. MEASUREMENTS AND MAIN RESULTS Number of eligible subjects, reasons for not starting therapy, number starting therapy, proportion completing therapy and median duration of INH therapy were calculated. Thirty-nine subjects were eligible for INH chemoprophylaxis: 34 (87%) received INH mixed directly in their methadone and five (13%) had their INH consumption supervised by a nurse. Among these subjects, 72% (28/39) completed therapy. Among the 11 subjects who discontinued INH, discharge from the methadone maintenance program was the most common reason--73% (8/11). Thus, among the 31 subjects who were not discharged from methadone maintenance, 90% (28/31) successfully completed INH prophylaxis. The median duration of therapy was 182 days. CONCLUSIONS Tuberculosis chemoprophylaxis using a liquid isoniazid-methadone admixture appears to be an effective approach to enhancing compliance with this therapy in methadone-maintained drug users.