Drug interactions
Lansoprazole + Levothyroxine
Severity: Moderate
Lansoprazole 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
Levothyroxine absorption depends on gastric acidity, and PPIs may reduce absorption, leading to higher TSH and a need for increased dose in some patients. Evidence is mixed but the effect is documented in practice.
What this interaction means in plain words
Lansoprazole 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.
Lansoprazole belongs to Gastrointestinal Tract; Levothyroxine belongs to Endocrine.
Why it happens
Increased gastric pH impairs dissolution and absorption of oral levothyroxine.
What to do
Check TSH 6 to 8 weeks after starting or stopping the PPI and adjust levothyroxine dose as 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 Lansoprazole
- Lansoprazole + Mavacamten Contraindicated
- Lansoprazole + Rilpivirine Contraindicated
- Acalabrutinib + Lansoprazole Major
- Atazanavir + Lansoprazole Major
- Dacomitinib + Lansoprazole Major
- Dasatinib + Lansoprazole Major
Other interactions of Levothyroxine
Frequently asked questions
Can I take Lansoprazole with Levothyroxine?
MediHelp rates the interaction as moderate. Lansoprazole 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. Levothyroxine absorption depends on gastric acidity, and PPIs may reduce absorption, leading to higher TSH and a need for increased dose in some patients. Evidence is mixed but the effect is documented in practice.
How serious is the interaction between Lansoprazole 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: Check TSH 6 to 8 weeks after starting or stopping the PPI and adjust levothyroxine dose as needed.
What other medicines interact with Lansoprazole?
MediHelp also lists interactions of Lansoprazole with, for example, Mavacamten, Rilpivirine, Acalabrutinib. The full list is on the Lansoprazole page.
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