Drug interactions
Ethotoin + Levothyroxine
Severity: Moderate
Ethotoin 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
Hydantoin anticonvulsants can lower thyroid hormone levels through enzyme induction and displacement from binding proteins. Data for ethotoin specifically are limited, so the effect is extrapolated from phenytoin.
What this interaction means in plain words
Ethotoin 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.
Why it happens
Likely hepatic enzyme induction increasing levothyroxine clearance, with possible protein-binding displacement, extrapolated from phenytoin.
What to do
Monitor TSH and free T4 when ethotoin is started or stopped and adjust the levothyroxine dose based on results.
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 Levothyroxine
Frequently asked questions
Can I take Ethotoin with Levothyroxine?
MediHelp rates the interaction as moderate. Ethotoin 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. Hydantoin anticonvulsants can lower thyroid hormone levels through enzyme induction and displacement from binding proteins. Data for ethotoin specifically are limited, so the effect is extrapolated from phenytoin.
How serious is the interaction between Ethotoin 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: Monitor TSH and free T4 when ethotoin is started or stopped and adjust the levothyroxine dose based on results.
What other medicines interact with Levothyroxine?
MediHelp also lists interactions of Levothyroxine with, for example, Cholestyramine, Sodium iodide i-131, Tiratricol. The full list is on the Levothyroxine page.
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