Drug interactions
Levothyroxine + Omeprazole
Severity: Moderate
Levothyroxine and Omeprazole: 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 levothyroxine needs an acidic gastric environment for optimal dissolution and absorption. Long-term acid suppression with omeprazole may reduce absorption, and some patients show a rise in TSH or need a higher levothyroxine dose.
What this interaction means in plain words
Levothyroxine and Omeprazole 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.
Levothyroxine belongs to Endocrine; Omeprazole belongs to Gastrointestinal Tract.
Why it happens
Increased gastric pH reduces dissolution and absorption of oral levothyroxine tablets.
What to do
Check TSH 6 to 8 weeks after starting, stopping or changing the dose of omeprazole in patients on levothyroxine. Adjust the levothyroxine dose according to the TSH result.
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 Omeprazole
- Mavacamten + Omeprazole Contraindicated
- Omeprazole + Rilpivirine Contraindicated
- Acalabrutinib + Omeprazole Major
- Atazanavir + Omeprazole Major
- Citalopram + Omeprazole Major
- Clopidogrel + Omeprazole Major
Other interactions of Levothyroxine
Frequently asked questions
Can I take Levothyroxine with Omeprazole?
MediHelp rates the interaction as moderate. Levothyroxine and Omeprazole 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 levothyroxine needs an acidic gastric environment for optimal dissolution and absorption. Long-term acid suppression with omeprazole may reduce absorption, and some patients show a rise in TSH or need a higher levothyroxine dose.
How serious is the interaction between Levothyroxine and Omeprazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check TSH 6 to 8 weeks after starting, stopping or changing the dose of omeprazole in patients on levothyroxine. Adjust the levothyroxine dose according to the TSH result.
What other medicines interact with Omeprazole?
MediHelp also lists interactions of Omeprazole with, for example, Mavacamten, Rilpivirine, Acalabrutinib. The full list is on the Omeprazole page.
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