Drug interactions
Ferric oxyhydroxide + Levothyroxine
Severity: Moderate
Ferric oxyhydroxide and Levothyroxine: 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
Iron compounds bind levothyroxine in the gut and reduce its absorption, which may raise TSH and cause hypothyroid symptoms.
What this interaction means in plain words
Ferric oxyhydroxide and Levothyroxine 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.
Ferric oxyhydroxide belongs to Gastrointestinal Tract; Levothyroxine belongs to Endocrine.
Why it happens
Formation of insoluble complexes between iron and levothyroxine in the gastrointestinal tract.
What to do
Give levothyroxine at least 4 hours before ferric oxyhydroxide and monitor TSH.
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 Ferric oxyhydroxide
Other interactions of Levothyroxine
Frequently asked questions
Can I take Ferric oxyhydroxide with Levothyroxine?
MediHelp rates the interaction as moderate. Ferric oxyhydroxide and Levothyroxine 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. Iron compounds bind levothyroxine in the gut and reduce its absorption, which may raise TSH and cause hypothyroid symptoms.
How serious is the interaction between Ferric oxyhydroxide and Levothyroxine?
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 before ferric oxyhydroxide and monitor TSH.
What other medicines interact with Ferric oxyhydroxide?
MediHelp also lists interactions of Ferric oxyhydroxide with, for example, Doxycycline, Acetylsalicylic acid, Cefalexin. The full list is on the Ferric oxyhydroxide page.
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