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DTG Dose with Rifampicin — SCE Infectious Diseases MCQ

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ModerateTuberculosisDTG Dose with RifampicinSCE Infectious Diseases

A 28-year-old man with HIV on DTG/TAF/FTC has been virally suppressed for 3 years. He is diagnosed with active pulmonary TB. Standard RHZE is started. What specific Dolutegravir dose adjustment is needed?

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Correct answer: D — Increase Dolutegravir to 50 mg BD when co-administered with Rifampicin

Rifampicin induces UGT1A1 and CYP3A4, reducing Dolutegravir levels by approximately 50%. The INSPIRING trial demonstrated that DTG 50 mg BD (doubled from standard 50 mg OD) achieves adequate DTG levels during Rifampicin co-administration. This is the BHIVA-recommended approach. An alternative is to substitute Rifabutin for Rifampicin (Rifabutin is a weaker inducer allowing standard DTG dosing), but Rifampicin is the standard first-line agent in NICE TB guidelines. When Rifampicin is stopped, DTG must be reduced back to 50 mg OD.

Reference: https://www.nice.org.uk/guidance/conditions-and-diseases/infections