Drug interactions
Glipizide-metformin + Phenytoin
Severity: Moderate
Glipizide-metformin 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 raise blood glucose, and may weaken the effect of antidiabetic therapy. Phenytoin also induces CYP2C9, which may lower glipizide levels.
What this interaction means in plain words
Glipizide-metformin 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.
Glipizide-metformin belongs to Endocrine; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin suppresses pancreatic insulin release and induces CYP2C9 metabolism of glipizide.
What to do
Monitor blood glucose when phenytoin is started, stopped or changed. Increase the antidiabetic dose if control worsens, and lower it after phenytoin withdrawal.
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 Glipizide-metformin
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 Glipizide-metformin with Phenytoin?
MediHelp rates the interaction as moderate. Glipizide-metformin 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 raise blood glucose, and may weaken the effect of antidiabetic therapy. Phenytoin also induces CYP2C9, which may lower glipizide levels.
How serious is the interaction between Glipizide-metformin 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 when phenytoin is started, stopped or changed. Increase the antidiabetic dose if control worsens, and lower it after phenytoin withdrawal.
What other medicines interact with Glipizide-metformin?
MediHelp also lists interactions of Glipizide-metformin with, for example, Contrast media, Diatrizoate meglumine / diatrizoate, Diatrizoate. The full list is on the Glipizide-metformin page.
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