Source: Chest  |  Posted 9 years ago

Isoniazid therapy results in lower rates of hepatotoxicity compared with pyrazinamide plus rifampin for the treatment of latent tuberculosis.

Severe hepatotoxicity may also occur with pyrazinamide plus rifampin, but this can be avoided by implementing intensive monitoring of liver enzymes, according to investigators.

The investigators, from the Brody School of Medicine at East Carolina University in Greenville, North Carolina, United States, compared the two treatments in 224 patients.

One hundred fourteen patients received six months of daily treatment with isoniazid and 110 patients received two months of daily treatment with pyrazinamide and rifampin.

Treatment completion and hepatotoxicity were assessed. Hepatotoxicity was defined as a fourfold or greater increase in alanine transaminase. A 40-fold increase in alanine transaminase indicated severe hepatotoxicity.

Results showed that 59% of the isoniazid group and 71% of the pyrazinamide plus rifampin group completed treatment.

Thirteen percent of the pyrazinamide plus rifampin patients exhibited hepatotoxicity compared with 4% of the isoniazid patients.

Severe hepatotoxicity was detected in 2 out of 43 pyrazinamide plus rifampin patients who received treatment before the implementation of an intensive liver enzyme monitoring program. Once the monitoring program was in place, there were no more instances of severe hepatotoxicity.

Risk of hepatotoxicity is three times greater with pyrazinamide plus rifampin compared with isoniazid, the investigators conclude.