Hepatoxicity of latent TB treatment

From the CDC an analysis of 4 years of data;

Historically the incidence has been estimated at 1 per 1,000 patients who begin treatment but the lack of specific diagnostic criteria and heterogeneous definitions complicate comparisons across studies.

Determining the actual figure was

made difficult by the absence of reliable denominators for the number of persons initiating INH treatment, which has been estimated at 291,000 to 433,000 per year

Over the period

17 patients with events meeting the SAE (severe adverse events) definition had received INH therapy and experienced liver injury. Of the 17 patients, two were children aged <15 years

The effects of hepatoxicity are dire

All patients had received INH therapy and had experienced severe liver injury. Five patients, including one child, underwent liver transplantation. Five adults died, including one liver transplant recipient. 

Correlation is unknown

Because the demographic characteristics of the patients who begin LTBI treatment with INH remain unknown, the risk factors for INH-associated liver injury cannot be determined conclusively.

Other therapies have been canvassed

such as 4 or 6 months of rifampin (9), 3 months of INH and rifampin (the preferred regimen in the United Kingdom, or 3 months of once-weekly INH and rifapentine, a regimen currently under investigation (CDC, unpublished data, 2010.

but for the moment

Until an equally effective, better-tolerated regimen is developed, 9 months of INH therapy remains the mainstay of LTBI treatment.

Whilst the rates are relatively low once hepatoxicity occurs the risk of serious injury and/or mortality remain high.