Drug interactions
Phenytoin + Saxagliptin-metformin
Severity: Moderate
Phenytoin and Saxagliptin-metformin: 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 reduce insulin release and cause hyperglycemia, which may weaken the glycemic control achieved with saxagliptin-metformin. Glucose may fall again after phenytoin is withdrawn, which can lead to hypoglycemia if doses are not adjusted.
What this interaction means in plain words
Phenytoin and Saxagliptin-metformin 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 belongs to Central Nervous System; Saxagliptin-metformin belongs to Endocrine.
Why it happens
Pharmacodynamic antagonism: phenytoin inhibits pancreatic insulin secretion; phenytoin also induces CYP enzymes, though saxagliptin is mainly a CYP3A4/5 substrate and may be affected by induction.
What to do
Monitor blood glucose when phenytoin is started or stopped and adjust the antidiabetic regimen accordingly. Watch for reduced saxagliptin efficacy given enzyme induction.
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 Saxagliptin-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 Phenytoin with Saxagliptin-metformin?
MediHelp rates the interaction as moderate. Phenytoin and Saxagliptin-metformin 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 reduce insulin release and cause hyperglycemia, which may weaken the glycemic control achieved with saxagliptin-metformin. Glucose may fall again after phenytoin is withdrawn, which can lead to hypoglycemia if doses are not adjusted.
How serious is the interaction between Phenytoin and Saxagliptin-metformin?
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 or stopped and adjust the antidiabetic regimen accordingly. Watch for reduced saxagliptin efficacy given enzyme induction.
What other medicines interact with Saxagliptin-metformin?
MediHelp also lists interactions of Saxagliptin-metformin with, for example, Atazanavir, Clozapine, Contrast media. The full list is on the Saxagliptin-metformin page.
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