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Latent tuberculosis infection before TNF inhibitor therapy — SCE Rheumatology MCQ

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ModerateTuberculosisLatent tuberculosis infection before TNF inhibitor therapySCE Rheumatology

A 54-year-old man with anti-CCP-positive rheumatoid arthritis has persistent high disease activity despite methotrexate and sulfasalazine. Infliximab is planned. During pre-treatment assessment, he reports recent household contact with a person who had infectious pulmonary tuberculosis. An interferon-gamma release assay is positive. The tuberculosis service has excluded active disease after clinical assessment and chest imaging. Six weeks ago, he had an unprovoked pulmonary embolism and remains in the treatment phase with apixaban 5 mg twice daily. Liver biochemistry is normal, he drinks minimal alcohol, and testing for HIV, hepatitis B and hepatitis C is negative. Which latent tuberculosis treatment regimen is most appropriate?

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Correct answer: E — Isoniazid with pyridoxine for 6 months

Explanation lettering: D = shown as A · E = shown as B · B = shown as C · A = shown as D · C = shown as E

This patient has latent tuberculosis infection: he has relevant exposure and a positive IGRA, but the tuberculosis service has excluded active disease. Preventive treatment is indicated because he is younger than 65 years and is about to receive a TNF inhibitor, which substantially increases the risk of progression to active tuberculosis. His normal liver biochemistry and absence of important hepatotoxicity risk factors permit isoniazid treatment. NICE recommends either 3 months of isoniazid plus rifampicin or 6 months of isoniazid for latent tuberculosis, with the latter preferred when interactions with rifamycins are a concern. Rifampicin strongly induces CYP3A4 and P-glycoprotein, reducing apixaban exposure by approximately half; the apixaban SmPC states that apixaban should not be used for treatment of DVT or pulmonary embolism with such strong inducers because efficacy may be compromised. Six months of isoniazid with pyridoxine therefore avoids the decisive interaction. A is inappropriate because untreated latent infection poses increased risk during infliximab therapy. B is normally a valid shorter regimen but is unsuitable during therapeutic apixaban. D has the same interaction and is not a NICE-listed standard latent tuberculosis regimen. E is the standard regimen for active drug-sensitive tuberculosis without CNS involvement, which has been excluded here.

Reference: Tuberculosis (NG33): Recommendations (16 February 2024) — https://www.nice.org.uk/guidance/ng33/chapter/Recommendations Apixaban 2.5 mg Film-coated Tablets: Summary of Product Characteristics (7 July 2026) — https://www.medicines.org.uk/emc/product/100606/smpc