Does Estrogens Interact with Levothyroxine And Liothyronine?
Moderate interaction. Estrogens increase serum thyroxine-binding globulin, potentially decreasing free levothyroxine. Patients without functioning thyroid gland may require increased thyroid dose.
Source & how this summary was prepared
This interaction summary was extracted from FDA drug labeling through openFDA, using automated processing and AI assistance. NIH/NLM RxNorm helps organize drug names.
Read the saved source label on DailyMed →
A separate current-label comparison has not been recorded for this page. Read about our extraction process.
- Interaction classification
- Moderate
- Levothyroxine And Liothyronine Class
- l-Triiodothyronine
- Management
- Confirm exact products with your pharmacist
- Data Source
- U.S. FDA via OpenFDA
How this interaction works
Increases serum thyroxine-binding globulin
What To Tell Your Doctor or Pharmacist
If you are taking Estrogens and your doctor is considering prescribing Levothyroxine And Liothyronine (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider