Drug interactions
Glyburide + Phenytoin
Severity: Moderate
Glyburide 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 may reduce glyburide levels and weaken glycemic control. Phenytoin can also impair insulin secretion, which may further raise glucose.
What this interaction means in plain words
Glyburide 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.
Glyburide belongs to Endocrine; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP2C9 and CYP3A4, increasing glyburide metabolism.
What to do
Monitor blood glucose and HbA1c and increase the glyburide dose if needed. 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 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
Other interactions of Glyburide
- Bosentan + Glyburide Contraindicated
- Cholic acid + Glyburide Major
- Ciprofloxacin + Glyburide Major
- Clarithromycin + Glyburide Major
- Fluconazole + Glyburide Major
- Glyburide + Insulin degludec-liraglutide Major
Frequently asked questions
Can I take Glyburide with Phenytoin?
MediHelp rates the interaction as moderate. Glyburide 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 may reduce glyburide levels and weaken glycemic control. Phenytoin can also impair insulin secretion, which may further raise glucose.
How serious is the interaction between Glyburide 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 glyburide dose if needed. Reassess when phenytoin is stopped.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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