Treatment of Latent Tuberculosis Infection (LTBI) is medication that is given to people who have latent TB infection to prevent them from developing TB disease. High-risk people should be evaluated for LTBI if they have a positive skin test reaction, regardless of their age. Sometimes LTBI is given to people who have a negative skin test result, such as high-risk contacts and children younger than 6 months old who have been exposed to active TB.
All patients being considered for LTBI should receive a medical evaluation to:
- Exclude the possibility of TB disease
- Determine whether they have ever been treated for TB infection or disease
- Identify any medical problems that may complicate therapy or require more careful monitoring
People who are suspected of having TB disease or who have been documented as adequately treated for latent TB infection or disease should not be given TLTBI.
The usual regimen for LTBI is isoniazid given daily for 9 months for all patients. Patients should be clinically evaluated every month for signs of hepatitis and other adverse reactions to isoniazid. They should also be educated about the symptoms caused by adverse reactions to isoniazid and instructed to seek medical attention immediately if these symptoms occur. In addition, people at greatest risk for hepatitis should have liver function tests before starting isoniazid. Four months of rifampin is an acceptable alternative regimen for LTBI.
TB disease must be treated for at least 6 months; in some cases, treatment lasts even longer. The initial regimen for treating TB disease should include four drugs: isoniazid, rifampin, pyrazinamide, and ethambutol. When the drug susceptibility results are available, clinicians may change the regimen accordingly. TB disease must be treated with at least two drugs to which the bacilli are susceptible. Using only one drug to treat TB disease can create a population of tubercle bacilli that is resistant to that drug. Drug resistance can also develop when patients do not take treatment as prescribed. Thus, to prevent relapse and drug resistance, clinicians must prescribe an adequate regimen and make sure that patients adhere to treatment. The best way to ensure that patients adhere to treatment is to use directly observed therapy (DOT).
There are several options for daily and intermittent treatment. For children with certain types of extrapulmonary TB, pregnant women, and people with drug-resistant TB, treatment may last longer or involve different regimens. Treatment of drug-resistant TB should always be done daily and under the supervision of a medical expert who is familiar with the treatment of drug-resistant TB.
All patients being treated for TB disease should be educated about the symptoms caused by adverse reactions to the drugs they are taking and instructed to seek medical attention immediately if they have symptoms of a serious side effect. Patients should be seen by a clinician at least monthly during treatment and evaluated for possible adverse reactions. In addition, before starting treatment, patients may have baseline tests to help clinicians detect any abnormalities that may complicate treatment.
Patients who are not receiving directly observed therapy should be carefully monitored for adherence to treatment. However, the only way to ensure adherence to treatment is to always directly observe therapy.
To determine whether a patient is responding to treatment, clinicians should do clinical evaluations and bacteriologic evaluations during treatment. Patients should be carefully reevaluated if their:
- Symptoms do not improve during the first 2 months of treatment
- Symptoms worsen after improving initially
- Culture results have not become negative after 2 months of treatment
- Culture results become positive after being negative
In some situations, clinicians may also use X-rays to monitor a patient's response to treatment for pulmonary TB.
The treatment of TB can be complicated, especially in patients who fail to respond to treatment, who relapse, or who have drug-resistant TB or adverse reactions to medications. Clinicians who do not have experience with these situations should consult an expert. The New Jersey Medical School Global Tuberculosis Institute at Rutgers is qualified to assist clinicians in consultation to treat their difficult TB patients.