A 56-year-old woman with iron deficiency anaemia takes ferrous sulphate 200 mg daily and also calcium carbonate and alendronic acid. After 4 weeks, her fatigue persists. Which recommendation would improve ferrous sulphate efficacy?

A 56-year-old woman with iron deficiency anaemia takes ferrous sulphate 200 mg daily and also calcium carbonate and alendronic acid. After 4 weeks, her fatigue persists. Which recommendation would improve ferrous sulphate efficacy?

• A. Take ferrous sulphate with calcium carbonate to enhance absorption.
• B. Take ferrous sulphate on an empty stomach at least 2 hours before or after calcium carbonate tablets.
• C. Stop ferrous sulphate and rely on diet.
• D. Increase ferrous sulphate dose to 400 mg daily.

Answer: (B)

Iron absorption is hindered when iron is taken together with calcium-containing products, such as calcium carbonate, because calcium can bind to iron in the gut and form insoluble complexes that the body can’t absorb. To improve the effectiveness of ferrous sulphate, it should be taken apart from calcium-containing tablets. Taking it on an empty stomach helps absorption further, so spacing the iron by at least two hours before or after calcium carbonate avoids the interaction. This is why the recommended approach is to take ferrous sulphate on an empty stomach and at least two hours before or after calcium carbonate. Taking iron with calcium would not improve absorption, relying on diet alone won’t correct the deficiency, and simply increasing the iron dose doesn’t address the reduced absorption and could worsen side effects.

Iron absorption is hindered when iron is taken together with calcium-containing products, such as calcium carbonate, because calcium can bind to iron in the gut and form insoluble complexes that the body can’t absorb. To improve the effectiveness of ferrous sulphate, it should be taken apart from calcium-containing tablets. Taking it on an empty stomach helps absorption further, so spacing the iron by at least two hours before or after calcium carbonate avoids the interaction.

This is why the recommended approach is to take ferrous sulphate on an empty stomach and at least two hours before or after calcium carbonate. Taking iron with calcium would not improve absorption, relying on diet alone won’t correct the deficiency, and simply increasing the iron dose doesn’t address the reduced absorption and could worsen side effects.