From the Guidelines
Short-course (3-4 months) rifamycin-based treatment regimens are preferred over longer-course (6-9 months) isoniazid monotherapy for the treatment of latent tuberculosis (TB) infection. The treatment of LTBI typically involves one of several medication regimens to prevent progression to active TB disease. According to the guidelines for the treatment of latent tuberculosis infection: recommendations from the National Tuberculosis Controllers Association and CDC, 2020 1, the preferred treatment regimens include 3 months of once-weekly isoniazid plus rifapentine, 4 months of daily rifampin, or 3 months of daily isoniazid plus rifampin.
Key Considerations
- Before starting treatment, patients should undergo baseline liver function tests, and those on isoniazid should take vitamin B6 (pyridoxine) 25-50mg daily to prevent peripheral neuropathy 1.
- Monthly monitoring for side effects is important, particularly hepatotoxicity, which may present as nausea, vomiting, abdominal pain, or jaundice.
- Treatment should be initiated after ruling out active TB disease through chest X-ray and symptom screening.
- The medications work by killing slowly replicating TB bacteria that remain dormant in the body, reducing the lifetime risk of developing active TB disease from about 5-10% to less than 1% 1.
Treatment Regimens
- 3 months of once-weekly isoniazid plus rifapentine
- 4 months of daily rifampin
- 3 months of daily isoniazid plus rifampin
- Alternative treatment regimens include daily isoniazid for 6 or 9 months, although these have higher toxicity risk and lower treatment completion rates than shorter rifamycin-based regimens 1.
Clinical Decision Making
When deciding on a treatment regimen, clinicians should consider the patient's ability to tolerate the medication, potential drug-drug interactions, and the presence of any underlying medical conditions that may affect treatment outcomes. The guidelines provide a framework for clinicians to make informed decisions about the treatment of LTBI, with the goal of preventing progression to active TB disease and reducing the risk of morbidity and mortality.
From the FDA Drug Label
PRIFTIN is indicated in adults and children 2 years and older for the treatment of latent tuberculosis infection caused by Mycobacterium tuberculosis in patients at high risk of progression to tuberculosis disease PRIFTIN must always be used in combination with isoniazid as a 12-week once-weekly regimen for the treatment of latent tuberculosis infection
The treatment for latent tuberculosis (TB) infection is PRIFTIN (rifapentine) in combination with isoniazid for 12 weeks, administered once weekly as directly observed therapy 2.
- The recommended dose of PRIFTIN is based on the patient's weight, up to a maximum of 900 mg once weekly.
- The recommended dose of isoniazid is 15 mg/kg (rounded to the nearest 50 mg or 100 mg) up to a maximum of 900 mg once weekly for adults and children 12 years and older, and 25 mg/kg (rounded to the nearest 50 mg or 100 mg) up to a maximum of 900 mg once weekly for children 2 to 11 years. Key considerations:
- Active tuberculosis disease should be ruled out before initiating treatment for latent tuberculosis infection.
- PRIFTIN in combination with isoniazid is not recommended for individuals presumed to be exposed to rifamycin-resistant or isoniazid-resistant M. tuberculosis. 2 2
From the Research
Treatment Options for Latent Tuberculosis Infection
The treatment for latent tuberculosis (TB) infection includes several options, each with its own efficacy and potential side effects. The main treatment options are:
- 9 months of daily self-administered isoniazid (INH) 3, 4
- 2 months of rifampin and pyrazinamide 3
- 3 to 4 months of INH and rifampin 3, 5
- 4 months of rifampin monotherapy 3, 4
- 3 months of once weekly directly observed isoniazid-rifapentine 6, 4
- 3 months of daily self-administered isoniazid-rifampin 4
Efficacy and Safety of Treatment Options
The efficacy of these treatment options varies, with 9 months of INH having an efficacy of more than 90% if completed properly 3. However, INH is associated with serious adverse events, including hepatotoxicity 3, 7. The 2 months of rifampin and pyrazinamide regimen has excellent efficacy in experimental studies and randomized trials, but is associated with an unacceptably high rate of severe liver toxicity in non-HIV-infected adults 3. The 3 to 4 months of INH and rifampin regimen has equivalent effectiveness to 6 months of INH, but with similar completion and toxicity rates 3. The 4 months of rifampin monotherapy has been found to have significantly better completion and less toxicity than 9 months of INH 3.
Comparison of Treatment Options
Studies have compared the adverse event profiles of different treatment options, with the INH/RPT-3 regimen (12 doses of isoniazid and rifapentine given once weekly) appearing to have a generally favorable adverse event profile 6. However, the reporting of adverse events was inconsistent and limited, making it difficult to draw firm conclusions. Other studies have found that short-course regimens, such as 4 months of rifampin monotherapy, have higher completion rates and lower hepatotoxicity rates compared to 9 months of INH 7.
Factors Affecting Treatment Choice
The choice of treatment for latent TB infection depends on various factors, including the patient's individual characteristics, the presence of comorbidities, and the potential for drug interactions 4. It is essential to monitor patients for potential adverse clinical events and to utilize strategies to promote adherence to treatment 4. Safer, more cost-effective, and more easily completed regimens are needed to improve treatment outcomes and prevent additional TB disease 4.