Drug interactions
Metformin-pioglitazone + Phenytoin
Severity: Moderate
Metformin-pioglitazone and Phenytoin: 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
Phenytoin can inhibit insulin secretion and cause hyperglycemia. As an enzyme inducer, it may also reduce pioglitazone exposure through CYP induction. Both effects may reduce glycemic control.
What this interaction means in plain words
Metformin-pioglitazone and Phenytoin 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; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin inhibits pancreatic insulin release and induces CYP2C8/CYP3A4, which may lower pioglitazone levels.
What to do
Monitor blood glucose and HbA1c, and increase the antidiabetic dose if control worsens. Reassess when phenytoin is stopped.
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 Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Frequently asked questions
Can I take Metformin-pioglitazone with Phenytoin?
MediHelp rates the interaction as moderate. Metformin-pioglitazone and Phenytoin 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. Phenytoin can inhibit insulin secretion and cause hyperglycemia. As an enzyme inducer, it may also reduce pioglitazone exposure through CYP induction. Both effects may reduce glycemic control.
How serious is the interaction between Metformin-pioglitazone and Phenytoin?
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, and increase the antidiabetic dose if control worsens. Reassess when phenytoin is stopped.
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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