From the Guidelines
Latent tuberculosis infection (LTBI) should be treated with one of the preferred rifamycin-based regimens, including 3 months of once-weekly isoniazid plus rifapentine, 4 months of daily rifampin, or 3 months of daily isoniazid plus rifampin, as these regimens have been shown to be effective and have high treatment completion rates. These regimens are recommended by the National Tuberculosis Controllers Association (NTCA) and CDC, based on a systematic literature review and evaluation of clinical trials 1. The preferred regimen of once-weekly isoniazid plus rifapentine for 3 months (3HP) consists of isoniazid 15 mg/kg (maximum 900 mg) plus rifapentine 600-900 mg (weight-based) once weekly for 12 weeks.
Key Considerations
- Before starting treatment, active TB must be ruled out through symptom screening, chest X-ray, and sometimes sputum testing 1.
- Baseline liver function tests are recommended, especially for those with risk factors for hepatotoxicity 1.
- Monthly monitoring for adverse effects is essential during treatment 1.
- Treatment completion is defined by taking at least 80% of doses within the recommended timeframe 1.
Alternative Regimens
- Daily isoniazid monotherapy for 6-9 months (5 mg/kg, maximum 300 mg daily) is an alternative regimen, but it has a higher toxicity risk and lower treatment completion rates than shorter rifamycin-based regimens 1.
- Daily rifampin for 4 months (10 mg/kg, maximum 600 mg daily) and daily isoniazid plus rifampin for 3 months are also alternative regimens 1.
Priority Groups
- Recent contacts of TB cases, immunocompromised individuals, those with HIV, and persons from high-prevalence countries are priority groups for LTBI testing and treatment 1.
- These regimens effectively reduce the risk of progression to active TB by 60-90%, with shorter rifampin-containing regimens offering better completion rates and fewer side effects than traditional 9-month isoniazid therapy 1.
From the FDA Drug Label
Although there have not been the same kinds of carefully conducted controlled trials of treatment of Extra pulmonary tuberculosis as for pulmonary disease, increasing clinical experience indicates that a 6 to 9 month short-course regimen is effective For Preventative Therapy of Tuberculosis Before isoniazid preventive therapy is initiated, bacteriologically positive or radiographically progressive tuberculosis must be excluded. Adults over 30 Kg: 300 mg per day in a single dose. Infants and Children: 10 mg/kg (up to 300 mg daily) in a single dose
The management of latent tuberculosis involves the use of isoniazid for preventative therapy. The recommended dosage is 300 mg per day for adults over 30 kg and 10 mg/kg (up to 300 mg daily) for infants and children. The treatment should be continued for a sufficient period, typically 6 to 9 months, to ensure effectiveness 2.
- Key considerations:
- Exclude bacteriologically positive or radiographically progressive tuberculosis before initiating preventative therapy
- Use isoniazid as the primary medication for preventative therapy
- Monitor patient compliance using methods such as the Potts-Cozart test or isoniazid test strips 2
- Consider concomitant administration of pyridoxine (B6) in malnourished patients or those predisposed to neuropathy 2
From the Research
Latent Tuberculosis Management
- Latent tuberculosis infection can be treated with various regimens, including isoniazid, rifampin, and rifapentine 3, 4, 5, 6.
- A 2-month regimen of rifampin and pyrazinamide was associated with an increased risk for grade 3 or 4 hepatotoxicity compared with a 6-month regimen of isoniazid 3.
- The 3-month regimen of isoniazid and rifapentine (3HP) was found to be superior to the 9-month regimen of isoniazid (9H) in terms of hepatotoxicity, efficacy, and completion rate 4.
- A population-based study found that treatment with 4 months of rifampin (4R) had lower hepatotoxicity, higher completion rates, and lower direct health system costs compared to 9 months of isoniazid (9H) 5.
- A systematic review and meta-analysis found that the 3-month isoniazid-rifapentine regimen was as safe and effective as other recommended latent tuberculosis infection regimens and achieved significantly higher treatment completion rates 6.
- Isoniazid-induced acute liver failure is a potential risk during preventive therapy for latent tuberculosis infection, highlighting the importance of monitoring liver function during treatment 7.
Treatment Regimens
- Isoniazid: 6-9 months 3, 4, 5, 6
- Rifampin: 2-4 months 3, 5
- Rifapentine: 3 months 4, 6
- Combination regimens: rifampin and pyrazinamide, isoniazid and rifapentine 3, 4, 6