Drug interactions
Levothyroxine + Metformin-sitagliptin
Severity: Moderate
Levothyroxine and Metformin-sitagliptin: 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
Thyroid hormone increases hepatic glucose output and metabolic rate, and over-replacement can worsen glycemic control. Patients with diabetes may need more antidiabetic therapy when levothyroxine is started or increased.
What this interaction means in plain words
Levothyroxine and Metformin-sitagliptin 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; Metformin-sitagliptin belongs to Endocrine.
Why it happens
Thyroid hormone enhances gluconeogenesis and glucose absorption and increases insulin clearance, opposing antidiabetic drug effects.
What to do
Monitor blood glucose when levothyroxine is started or its dose changed, and keep TSH within target to avoid over-replacement.
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-sitagliptin
Other interactions of Levothyroxine
Frequently asked questions
Can I take Levothyroxine with Metformin-sitagliptin?
MediHelp rates the interaction as moderate. Levothyroxine and Metformin-sitagliptin 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. Thyroid hormone increases hepatic glucose output and metabolic rate, and over-replacement can worsen glycemic control. Patients with diabetes may need more antidiabetic therapy when levothyroxine is started or increased.
How serious is the interaction between Levothyroxine and Metformin-sitagliptin?
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 levothyroxine is started or its dose changed, and keep TSH within target to avoid over-replacement.
What other medicines interact with Metformin-sitagliptin?
MediHelp also lists interactions of Metformin-sitagliptin with, for example, Clozapine, Contrast media, Diatrizoate meglumine / diatrizoate. The full list is on the Metformin-sitagliptin page.
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