Drug interactions
Ferrous fumarate + Thyroid desiccated
Severity: Moderate
Ferrous fumarate and Thyroid desiccated: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Oral iron binds thyroid hormone in the gut and reduces its absorption. This can raise TSH and cause hypothyroid symptoms in patients on stable thyroid replacement.
What this interaction means in plain words
Ferrous fumarate and Thyroid desiccated can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Iron forms insoluble complexes with thyroid hormones in the gastrointestinal lumen, reducing absorption.
What to do
Separate thyroid desiccated and iron by at least 4 hours. Check TSH about 6 to 8 weeks after starting or stopping iron and adjust thyroid dose if needed.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Ferrous fumarate
Frequently asked questions
Can I take Ferrous fumarate with Thyroid desiccated?
MediHelp rates the interaction as moderate. Ferrous fumarate and Thyroid desiccated can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Oral iron binds thyroid hormone in the gut and reduces its absorption. This can raise TSH and cause hypothyroid symptoms in patients on stable thyroid replacement.
How serious is the interaction between Ferrous fumarate and Thyroid desiccated?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Separate thyroid desiccated and iron by at least 4 hours. Check TSH about 6 to 8 weeks after starting or stopping iron and adjust thyroid dose if needed.
What other medicines interact with Ferrous fumarate?
MediHelp also lists interactions of Ferrous fumarate with, for example, Ciprofloxacin, Acetohydroxamic acid, Aluminum hydroxide. The full list is on the Ferrous fumarate page.
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