A patient on anti-TNF therapy (infliximab) for rheumatoid arthritis is found to have IGRA (interferon-gamma release assay) positive but no active disease on chest X-ray. The preferred drug regimen for latent TB infection (LTBI) in this scenario is:
- A Rifampicin + isoniazid for 3 months (3RH) or isoniazid + rifapentine weekly for 3 months (3HP) ✓
- B Rifampicin 600 mg daily for 4 months
- C Isoniazid 300 mg daily for 9 months (9H)
- D No treatment needed as IGRA has low specificity in immunosuppressed patients
Correct answer: A. Rifampicin + isoniazid for 3 months (3RH) or isoniazid + rifapentine weekly for 3 months (3HP)
Explanation
For LTBI in patients about to receive biologic/TNF-inhibitor therapy, WHO and NTEP 2023 guidelines recommend shorter regimens: 3-month rifampicin + isoniazid (3RH) or 3-month weekly isoniazid + rifapentine (3HP) for superior completion rates and similar efficacy to 9H. LTBI treatment should be initiated and completed (at least 4 weeks ideally) before starting anti-TNF therapy. IGRA is preferred over TST in BCG-vaccinated individuals and immunosuppressed patients as it has higher specificity.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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