Use, effectiveness and safety of isoniazid in the treatment of latent
tuberculosis infection, what do we know?
Abstract
Background The treatment strategy for latent tuberculosis (TB) infection
(LTBI) aims to promote a reduction in the number of cases that develop
into TB and, consequently, a reduction in the transmission of pathogenic
bacteria. Objectives The objective was to know the safety, effectiveness
and adherence of the use of INH in two pharmaceutical presentations
(300mg or 100mg tablet) reported in scientific studies. Methods A review
protocol was registered a priori with PROSPERO (number CRD42020176694).
The electronic databases Cochrane; PubMed; Embase; LILACS, Scopus, and
Web of Science were searched for studies on use of INH for LTBI. The
results and methods were presented in line with the PRISMA guidelines,
and the methodological quality of the included reviews was assessed
using the Quality Assessment Tool for Observational Cohort and
Cross-Sectional Studies. Results Most of the studies used isoniazid (H)
as a treatment for LTBI, with a duration of 9 months. There was
significant variation in the of use of isoniazid, ranging from 0.3% to
98.6% of the participants. A similar variation was found in the 52
studies that similarly presented the rate of adherence to treatment with
H, which ranged from 18% to 100% among study participants completing
INH treatment for LTBI. In studies, the adverse events reported most
frequent events reported were included hepatotoxicity, gastric
intolerance, and neuropathy, the rates of occurrence of these with
isoniazid, rang from < 1% to 48%. In the studies that
evaluated effectiveness of isoniazid for latent tuberculosis infection,
a variation from 0 to 19.7% of people who did not have active TB after
the follow-up period was observed, with the highest rate among
HIV-positive individuals. Conclusion Our findings indicate that
isoniazid is being widely used in the world as a prophylactic treatment
for tuberculosis, rates of adherence to isoniazid were above 50%. It is
important to emphasize the importance of keeping the follow-up of the
person who uses isoniazid due to the risk of developing unwanted events
resulting from the drug. Even with treatment challenges, we identified
low rates of people who used isoniazid and developed active tuberculosis
during the period they were followed. We believe that isoniazid
continues to contribute to tuberculosis control in the world and better
care actions are needed.