CDC Logo Tuberculosis Information CD-ROM   Image of people
jump over main navigation bar to content area
TB Guidelines
Surveillance Reports
Slide Sets
TB-Related MMWRs and Reports
Education/Training Materials
Ordering Information


U.S. Department of Health and Human Services


Core Curriculum on Tuberculosis, 2000

Chapter 6
Treatment of Latent TB Infection (LTBI)

Regimens for Specific Situations

Contacts of Isoniazid-Resistant TB
For persons who are known to be contacts of patients with isoniazid-resistant, rifampin-susceptible TB, a 4-month regimen of daily rifampin is recommended. In situations where rifampin cannot be used, rifabutin may be substituted.  For HIV-positive persons, a 2-month regimen with a rifamycin and pyrazinamide is an alternative.

Contacts of Multidrug-Resistant TB
For persons likely to have been infected with a strain of M. tuberculosis resistant to both isoniazid and rifampin, alternative regimens should be considered. Alternative regimens should consist of two drugs to which the infecting organism has demonstrated susceptibility. Potential alternative regimens include either 6-12 months of daily ethambutol and pyrazinamide or 6-12 months of pyrazinamide and a quinolone (i.e, levofloxacin, ofloxacin, or ciprofloxacin). Immunocompetent contacts may be treated for 6 months or observed without treatment. Immunocompromised contacts (e.g., HIV-positive persons) should be treated for 12 months. Persons receiving pyrazinamide and a quinolone antibiotic should be monitored closely for adverse effects. Some evidence suggests that the combination of pyrazinamide and ofloxacin may be poorly tolerated. 6 All persons with suspected multidrug-resistant LTBI should be followed for 2 years regardless of the treatment regimen.

Ethambutol at the usual dose is safe for children. The regimen of pyrazinamide and ethambutol for 9-12 months is recommended for children if the infecting organism has demonstrated susceptibility. When pyrazinamide and/or ethambutol cannot be used, a combination of two other drugs to which the infecting organism is likely susceptible is recommended.

Persons with Fibrotic Lesions
Patients who have a chest radiograph suggestive of old fibrotic lesions thought to represent previous TB, a positive tuberculin skin test (>=5 mm), no evidence of active disease, and no history of treatment for TB should be treated for LTBI. Acceptable regimen options include

  • 9 months of isoniazid
  • 4 months of rifampin (with or without isoniazid)

Patients who have a positive tuberculin skin test and radiographic findings suggestive of healed, primary TB (calcified solitary pulmonary nodules, calcified hilar lymph nodes, and apical pleural capping) are not at significantly increased risk of TB. Their risk for progression to TB disease and the need for treatment of LTBI should be determined by other risk factors and the size of the tuberculin reaction.

Pregnancy and Breast-feeding
Isoniazid administered either daily or twice-weekly are the preferred regimens for the treatment of LTBI in pregnant women. Such women taking isoniazid should also take pyridoxine (vitamin B6) supplementation. Although rifampin may be safe, there are no efficacy data supporting its use in this population.

For women who are at high risk for the progression of LTBI to active disease, especially those who are HIV-positive or who have been recently infected, initiation of therapy should not be delayed on the basis of pregnancy alone, even during the first trimester. For these women, careful clinical monitoring and/or lab monitoring should be conducted.

Breast-feeding is not contraindicated when a mother is being treated for LTBI. Likewise, the amount of isoniazid provided by breast milk is inadequate for the treatment of an infant. Infants whose breast-feeding mothers are taking isoniazid should receive supplemental pyridoxine.


Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination -

Please send comments/suggestions/requests to:, or to
CDC/Division of Tuberculosis Elimination
Communications, Education, and Behavioral Studies Branch
1600 Clifton Rd., NE - Mailstop E-10, Atlanta, GA 30333