Can You Take Levothyroxine with Omeprazole?
Last reviewed: · Source: US FDA drug label database
Long-term omeprazole can reduce levothyroxine absorption — take levothyroxine on an empty stomach and have thyroid levels rechecked after starting a PPI.
Is it safe to take Levothyroxine with Omeprazole?
Levothyroxine needs stomach acid for optimal absorption. Omeprazole and other PPIs suppress acid production, which can reduce levothyroxine absorption over time and cause TSH to creep up. The drugs can still be used together — millions of people take both — but thyroid function should be rechecked 6-8 weeks after starting or stopping a PPI, and the levothyroxine dose adjusted if needed.
How do Levothyroxine and Omeprazole interact?
Gastric acidity aids dissolution of levothyroxine tablets and its absorption in the jejunum/ileum. PPI-induced hypochlorhydria reduces bioavailability, with studies showing increased TSH in levothyroxine-treated patients after starting PPIs. Liquid or soft-gel levothyroxine formulations are less affected.
Data sourced from the US Food and Drug Administration (FDA) drug label database: OpenFDA levothyroxine label — drugs affecting gastric acidity.
Who should be careful?
Anyone whose hypothyroid symptoms return after starting omeprazole, people with previously stable TSH that rises unexpectedly, and pregnant women (where precise thyroid control is critical).
What if I've already taken Levothyroxine and Omeprazole?
No emergency — this is a slow absorption effect, not a toxic interaction. Take levothyroxine 30-60 minutes before breakfast with water, keep the PPI at a different time of day, and ask your GP for a TSH check 6-8 weeks after any PPI change.
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Frequently Asked Questions
Can I take omeprazole with levothyroxine?
Yes, but omeprazole may reduce levothyroxine absorption over time. Separate the doses and get TSH rechecked after starting the PPI.
How should I space levothyroxine and omeprazole?
Take levothyroxine first thing on an empty stomach, 30-60 minutes before food. Take omeprazole before a different meal, e.g. the evening meal.
Why is my TSH rising since starting omeprazole?
Reduced stomach acid can lower levothyroxine absorption. Your GP may need to raise your levothyroxine dose slightly or switch formulations.
Do all heartburn medicines affect levothyroxine?
All PPIs can. Antacids containing calcium, magnesium or aluminium also bind levothyroxine — separate those by at least 4 hours.