What is the standard treatment for latent tuberculosis (TB) infection?

Standard Treatment for Latent Tuberculosis Infection

The preferred treatment options for latent tuberculosis infection (LTBI) are 3 months of once-weekly isoniazid plus rifapentine or 4 months of daily rifampin due to their excellent efficacy, shorter duration, and better completion rates compared to traditional isoniazid regimens. 1

Recommended Treatment Regimens

Preferred Regimens:

• 3-month weekly rifapentine plus isoniazid (strong recommendation, moderate to high quality evidence) 2, 1
• 4-month daily rifampin alone (strong recommendation, moderate to high quality evidence) 2, 1

Alternative Regimens:

• 6-month daily isoniazid (strong recommendation, moderate quality evidence) 2
• 9-month daily isoniazid (strong recommendation, moderate quality evidence) 2, 1
• 3-4 month daily isoniazid plus rifampin (strong recommendation, moderate quality evidence) 2

Patient Selection for LTBI Testing and Treatment

LTBI testing and treatment should be prioritized for these high-risk groups:

• People living with HIV
• Adult and child contacts of pulmonary TB cases
• Patients initiating anti-TNF treatment
• Patients receiving dialysis
• Patients preparing for organ or hematological transplantation
• Patients with silicosis 2

Additionally, consider testing and treatment for:

• Prisoners
• Healthcare workers
• Immigrants from high TB burden countries
• Homeless persons
• Illicit drug users 2, 1

Pre-Treatment Evaluation

Before initiating LTBI treatment:

1. Rule out active TB disease through:

   • Symptom screening (cough, fever, night sweats, weight loss)
   • Chest radiography 2, 1
   • Collection of sputum specimens if pulmonary symptoms are present 2

2. Baseline laboratory testing:

   • Liver function tests for patients with risk factors (pregnancy, HIV infection, chronic liver disease, regular alcohol use) 1

Monitoring During Treatment

• Monthly clinical evaluations to assess for adverse effects, particularly hepatotoxicity 1
• Provide pyridoxine (vitamin B6) supplementation for patients on isoniazid to prevent peripheral neuropathy 1
• Discontinue isoniazid if transaminase levels exceed three times the upper limit of normal in symptomatic patients or five times the upper limit of normal in asymptomatic patients 3

Special Populations

HIV Co-infection

• LTBI treatment is strongly recommended for HIV-positive individuals with a positive tuberculin skin test (≥5 mm) 1
• Rifampin-based regimens should be used with caution due to potential drug interactions with antiretrovirals 1

Children

• Children ≥2 years: Can receive rifapentine plus isoniazid with weight-based dosing 1
• Children <2 years: 9 months of isoniazid is recommended 1

Pregnancy

• 9 months of isoniazid is the recommended regimen 1, 4
• Rifampin is not recommended for pregnant women 2
• Pyrazinamide is not recommended due to inadequate teratogenicity data 4

Common Pitfalls to Avoid

1. Failing to rule out active TB before starting LTBI treatment, which can lead to drug resistance and treatment failure 1

2. Adding a single drug to a failing regimen in cases of suspected drug resistance, which can promote further resistance. Always add ≥2 new drugs if treatment failure is suspected 2

3. Inadequate monitoring for hepatotoxicity, particularly with isoniazid regimens 1

4. Overlooking drug interactions with rifampin-containing regimens, which can interact with many medications including antiretrovirals 1

5. Using 2-month rifampin plus pyrazinamide regimen, which is not recommended due to increased hepatotoxicity risk 2

The selection of an LTBI treatment regimen should consider drug availability, potential for adverse effects, drug-drug interactions, and likelihood of treatment completion. Shorter rifamycin-based regimens are generally preferred when there are no contraindications due to their better completion rates and comparable efficacy to longer isoniazid regimens.