Of the 21 patients, 16 recovered and 5 died.
Findings from the investigations into these cases are included in the 31 August edition of the Centers for Disease Control and Prevention's (CDC's) Morbidity and Mortality Weekly Report (MMWR).
As a result, CDC and the American Thoracic Society are issuing revised treatment guidelines for latent tuberculosis infection (LTBI). These are to limit the circumstances in which the combination of RIF-PZA is prescribed, and to strengthen the level of patient counseling and monitoring recommended for LTBI treatment regimens.
For most individuals with LTBI, the new guidelines recommend the 9-month regimen of daily isoniazid (INH) as the preferred treatment.
CDC recommends providers use RIF-PZA with caution, especially in those currently taking other medications that have been associated with liver injury. Care should also be taken with alcoholic subjects, even if alcohol usage is discontinued during treatment.
However, with careful clinical and laboratory monitoring, as outlined in the recommendations, RIF-PZA remains an option for patients at high risk of developing active TB disease and who are unlikely to complete a 9-month regimen of isoniazid (INH).
For HIV-negative individuals with LTBI, the new guidelines recommend the 9-month regimen of daily INH as the standard treatment.
While available data do not suggest excessive risk of severe side-effects associated with RIF-PZA among HIV-positive individuals, providers should consider the use of INH when completion of this longer regimen can be assured.
The guidelines emphasize TB testing and treatment for people at high risk.
|Rifampin and pyrazinamide used with caution in those already at increased liver damage risk.
|Centers for Disease Control and Prevention|
Those at high risk of developing active TB include individuals with LTBI who are HIV-infected, those who were recent contacts of someone with active TB, and injection drug users. Residents or employees of high-risk congregate settings are also at increased risk.
Furthermore, providers are reminded that treatment is recommended for foreign-born people with LTBI, who have lived in the United States for less than 5 years and who were born in countries with high rates of TB.
After 5 years, treatment decisions should be made on the same basis as other patients.
As all regimens for treating LTBI have been associated with liver injury, careful monitoring during treatment is important to avoid severe damage.
Any additional cases of severe liver damage associated with treatment of LTBI should be reported to the CDC's Division of TB Elimination, they add.