Drug interactions
Liotrix + Metformin
Severity: Moderate
Liotrix and Metformin: 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
Liotrix contains levothyroxine and liothyronine, and thyroid hormone excess can raise blood glucose in diabetic patients. This may reduce the effect of metformin.
What this interaction means in plain words
Liotrix and Metformin 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
Thyroid hormone excess increases gluconeogenesis, glycogenolysis and gut glucose absorption, opposing metformin.
What to do
Monitor blood glucose when thyroid hormone therapy is started or changed and adjust metformin as needed. Watch for hypoglycemia if the thyroid dose is reduced.
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 Metformin
Frequently asked questions
Can I take Liotrix with Metformin?
MediHelp rates the interaction as moderate. Liotrix and Metformin 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. Liotrix contains levothyroxine and liothyronine, and thyroid hormone excess can raise blood glucose in diabetic patients. This may reduce the effect of metformin.
How serious is the interaction between Liotrix and Metformin?
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 blood glucose when thyroid hormone therapy is started or changed and adjust metformin as needed. Watch for hypoglycemia if the thyroid dose is reduced.
What other medicines interact with Metformin?
MediHelp also lists interactions of Metformin with, for example, Contrast media, Diatrizoate meglumine / diatrizoate, Diatrizoate. The full list is on the Metformin page.
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