Drug interactions
Metformin-pioglitazone + Sulfamethoxazole
Severity: Moderate
Metformin-pioglitazone and Sulfamethoxazole: 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
Sulfamethoxazole (usually combined with trimethoprim) may increase metformin exposure by competing for renal tubular secretion. Sulfonamides can also cause hypoglycemia on their own, and metformin accumulation is a concern in patients with renal impairment.
What this interaction means in plain words
Metformin-pioglitazone and Sulfamethoxazole 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
Competition for renal tubular secretion via OCT2/MATE transporters reduces metformin clearance; trimethoprim is the main inhibitor in combination products.
What to do
Monitor blood glucose and renal function during co-therapy, particularly in elderly or renally impaired patients. Consider reducing the metformin dose if glycemic or renal parameters change.
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
Frequently asked questions
Can I take Metformin-pioglitazone with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Metformin-pioglitazone and Sulfamethoxazole 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. Sulfamethoxazole (usually combined with trimethoprim) may increase metformin exposure by competing for renal tubular secretion. Sulfonamides can also cause hypoglycemia on their own, and metformin accumulation is a concern in patients with renal impairment.
How serious is the interaction between Metformin-pioglitazone and Sulfamethoxazole?
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 renal function during co-therapy, particularly in elderly or renally impaired patients. Consider reducing the metformin dose if glycemic or renal parameters change.
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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