Drug interactions
Metformin-pioglitazone + Trimethoprim
Severity: Moderate
Metformin-pioglitazone and Trimethoprim: 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
Trimethoprim raises metformin plasma concentrations, which may increase the risk of metformin adverse effects including lactic acidosis, especially in renal impairment. Trimethoprim can also slightly raise serum creatinine without a true fall in GFR.
What this interaction means in plain words
Metformin-pioglitazone and Trimethoprim 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-pioglitazone belongs to Endocrine; Trimethoprim belongs to Anti Bacterial.
Why it happens
Trimethoprim inhibits renal tubular transporters OCT2 and MATE1/MATE2-K, reducing metformin renal secretion.
What to do
Monitor renal function and for metformin toxicity, and consider reducing the metformin dose, particularly with eGFR below normal or with high-dose or prolonged trimethoprim.
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-pioglitazone
Other interactions of Trimethoprim
Frequently asked questions
Can I take Metformin-pioglitazone with Trimethoprim?
MediHelp rates the interaction as moderate. Metformin-pioglitazone and Trimethoprim 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. Trimethoprim raises metformin plasma concentrations, which may increase the risk of metformin adverse effects including lactic acidosis, especially in renal impairment. Trimethoprim can also slightly raise serum creatinine without a true fall in GFR.
How serious is the interaction between Metformin-pioglitazone and Trimethoprim?
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 renal function and for metformin toxicity, and consider reducing the metformin dose, particularly with eGFR below normal or with high-dose or prolonged trimethoprim.
What other medicines interact with Metformin-pioglitazone?
MediHelp also lists interactions of Metformin-pioglitazone with, for example, Contrast media, Diatrizoate meglumine / diatrizoate, Diatrizoate. The full list is on the Metformin-pioglitazone page.
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