Drug interactions
Metformin-sitagliptin + Niacin
Severity: Moderate
Metformin-sitagliptin and Niacin: 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
Niacin, especially at lipid-lowering doses, can raise blood glucose and impair glycemic control. This may reduce the effect of metformin and sitagliptin.
What this interaction means in plain words
Metformin-sitagliptin and Niacin 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.
Metformin-sitagliptin belongs to Endocrine; Niacin belongs to Cardiovascular.
Why it happens
Niacin induces insulin resistance and increases hepatic glucose output, opposing the antidiabetic drugs.
What to do
Monitor blood glucose and HbA1c when starting or adjusting niacin and increase antidiabetic therapy if 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 Metformin-sitagliptin
Other interactions of Niacin
- Alogliptin-metformin + Niacin Moderate
- Atorvastatin + Niacin Moderate
- Canagliflozin-metformin + Niacin Moderate
- Cholestyramine + Niacin Moderate
- Colestipol + Niacin Moderate
- Dapagliflozin-metformin + Niacin Moderate
Frequently asked questions
Can I take Metformin-sitagliptin with Niacin?
MediHelp rates the interaction as moderate. Metformin-sitagliptin and Niacin 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. Niacin, especially at lipid-lowering doses, can raise blood glucose and impair glycemic control. This may reduce the effect of metformin and sitagliptin.
How serious is the interaction between Metformin-sitagliptin and Niacin?
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 and HbA1c when starting or adjusting niacin and increase antidiabetic therapy if needed.
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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