Drug interactions
Metformin + Quinidine
Severity: Moderate
Metformin and Quinidine: 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
Metformin is eliminated by renal tubular secretion through OCT2 and MATE transporters. Cationic drugs such as quinidine can reduce this clearance and raise metformin exposure. This could add to the risk of gastrointestinal effects, and rarely lactic acidosis, in patients with reduced renal function.
What this interaction means in plain words
Metformin and Quinidine 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 belongs to Endocrine; Quinidine belongs to Anti Parasitic.
Why it happens
Quinidine inhibits renal cationic transporters (OCT2/MATE) that clear metformin.
What to do
Monitor glycemic control and renal function, and watch for signs of metformin toxicity. Reduce the metformin dose if adverse effects appear or renal function falls.
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 Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
Other interactions of Metformin
Frequently asked questions
Can I take Metformin with Quinidine?
MediHelp rates the interaction as moderate. Metformin and Quinidine 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 is eliminated by renal tubular secretion through OCT2 and MATE transporters. Cationic drugs such as quinidine can reduce this clearance and raise metformin exposure. This could add to the risk of gastrointestinal effects, and rarely lactic acidosis, in patients with reduced renal function.
How serious is the interaction between Metformin and Quinidine?
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 glycemic control and renal function, and watch for signs of metformin toxicity. Reduce the metformin dose if adverse effects appear or renal function falls.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine page.
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