Drug interactions
Levothyroxine + Polysaccharide iron
Severity: Moderate
Levothyroxine and Polysaccharide iron: 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 preparations can bind levothyroxine in the gut and reduce how much is absorbed. This may raise TSH and lead to hypothyroidism in patients who were previously well controlled.
What this interaction means in plain words
Levothyroxine and Polysaccharide iron 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 levothyroxine in the gastrointestinal tract, reducing its absorption.
What to do
Give levothyroxine at least 4 hours apart from the iron product. Check TSH about 6 to 8 weeks after starting or stopping iron and adjust the levothyroxine 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 Levothyroxine
Frequently asked questions
Can I take Levothyroxine with Polysaccharide iron?
MediHelp rates the interaction as moderate. Levothyroxine and Polysaccharide iron 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 preparations can bind levothyroxine in the gut and reduce how much is absorbed. This may raise TSH and lead to hypothyroidism in patients who were previously well controlled.
How serious is the interaction between Levothyroxine and Polysaccharide iron?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Give levothyroxine at least 4 hours apart from the iron product. Check TSH about 6 to 8 weeks after starting or stopping iron and adjust the levothyroxine dose if needed.
What other medicines interact with Levothyroxine?
MediHelp also lists interactions of Levothyroxine with, for example, Cholestyramine, Sodium iodide i-131, Tiratricol. The full list is on the Levothyroxine page.
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