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Levothyroxine absorption interaction — GPhC CRA MCQ

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ModerateEndocrine TherapeuticsLevothyroxine absorption interactionGPhC CRA

A 34-year-old woman starts levothyroxine 50micrograms daily. She also takes ferrous sulfate and calcium carbonate bought OTC. She asks how to take the medicines because she feels tired and wants them together in the morning. What would you advise the patient?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: D — Take levothyroxine on an empty stomach and separate it from iron and calcium.

Iron and calcium can reduce levothyroxine absorption, so separation is needed. Levothyroxine is commonly taken on an empty stomach with water, with consistent timing. Combining interacting supplements can contribute to persistent hypothyroid symptoms.

Reference: BNF; NICE CKS