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DTG-Iron Chelation — SCE Infectious Diseases MCQ

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EasyHIV MedicineDTG-Iron ChelationSCE Infectious Diseases

A 28-year-old man with HIV on DTG/TAF/FTC is prescribed a course of oral iron supplementation for iron deficiency anaemia. He takes his ART and iron tablets together at the same time. What interaction occurs?

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Correct answer: E — Divalent cations (iron, calcium, magnesium, aluminium) chelate Dolutegravir, reducing its absorption by up to 70% — DTG must be taken 2 hours before or 6 hours after iron

Dolutegravir (and other INSTIs including Bictegravir and Raltegravir) forms insoluble chelation complexes with polyvalent cations (Fe²⁺, Ca²⁺, Mg²⁺, Al³⁺), dramatically reducing INSTI absorption. DTG should be taken at least 2 hours before or 6 hours after iron supplements (or mineral supplements, antacids containing aluminium/magnesium). If taken with food containing calcium, DTG absorption is less affected (food-effect compensation). This interaction is frequently tested and clinically important — subtherapeutic DTG levels can lead to virological failure.

Reference: BHIVA 2025 – ART guidelines; BNF 2024 – Dolutegravir; Liverpool Drug Interactions