skip to main content

Levothyroxine and iron — GPhC CRA MCQ

Instant feedback + full explanation. One question, done properly.

ModerateDrug InteractionsLevothyroxine and ironGPhC CRA

A woman taking levothyroxine 100 micrograms each morning buys ferrous sulfate for iron deficiency. She says she takes her tablets together before breakfast to avoid forgetting. What would you advise the patient?

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

Reveal the answer and explanation

Correct answer: C — Separate ferrous sulfate and levothyroxine dosing by several hours

Iron salts can reduce levothyroxine absorption and cause loss of thyroid control. Separating administration by several hours is a practical counselling point. Thyroid function may need review if symptoms recur or if the interaction has been ongoing.

Reference: BNF