Am. J. Respir. Crit. Care Med.,
Volume 162, Number 3, September 2000, 989-993
Twice Weekly Isoniazid and Rifampin Treatment
of Latent Tuberculosis Infection in Canadian
Plains Aborigines
BRIAN D.
McNAB,
DARCY D.
MARCINIUK,
RIAZ A.
ALVI,
LEONARD
TAN,
and
VERNON H.
HOEPPNER
Division of Tuberculosis Control, Department of Medicine, and Department of Community Health and Epidemiology, and Research Center
for the Elimination of Tuberculosis, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Six months of twice weekly directly observed isoniazid and rifam-picin treatment of latent tuberculosis (TB) infection was implemented to improve the outcome of treatment. A total of 591 infected aborigines without previous tuberculosis or treatment of
latent TB infection received twice weekly isoniazid and rifampicin for 6 mo from 1992 to 1995. The outcome was compared with 403 infected aborigines without previous tuberculosis or treatment of
latent TB infection who received self-administered isoniazid daily
for 1 yr from 1986 to 1989. Of patients, 487 (82%) completed the
twice weekly 6-mo regimen compared with 77 (19%) who completed the daily 12-mo regimen. The main reason for incomplete
treatment was default. Both groups were followed over a 6-yr period. The rate of tuberculosis in the twice-weekly isoniazid and
rifampicin-treated patients was 0.9/1,000 patient-years compared
with 9/1,000 patient-years in the daily isoniazid-treated patients.
The rate of side effects was higher for directly observed treatment
patients, 136/1,000 patient-years of drugs, compared with 39/
1,000 patient-years for self-administered treatment patients. Life-threatening side effects such as skin allergic reactions and hepatitis were the same in both groups. A regimen of 52 doses of directly
observed twice weekly isoniazid and rifampicin is an effective and
well-tolerated regimen to improve the outcome of the treatment of
latent tuberculosis infection in a population with a high rate of default
with daily self-administered isoniazid.
