Drug interactions
Fosphenytoin + Saxagliptin-metformin
Severity: Moderate
Fosphenytoin 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, the active form of fosphenytoin, can raise blood glucose by inhibiting insulin secretion. This may weaken glycemic control in patients taking saxagliptin-metformin, and glucose may fall again once phenytoin is stopped.
What this interaction means in plain words
Fosphenytoin 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.
Fosphenytoin belongs to Central Nervous System; Saxagliptin-metformin belongs to Endocrine.
Why it happens
Pharmacodynamic antagonism through phenytoin-induced suppression of pancreatic insulin release.
What to do
Monitor blood glucose after starting, changing or stopping fosphenytoin and adjust antidiabetic therapy as needed. Watch for hypoglycemia when phenytoin is withdrawn.
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 Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Fosphenytoin with Saxagliptin-metformin?
MediHelp rates the interaction as moderate. Fosphenytoin 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, the active form of fosphenytoin, can raise blood glucose by inhibiting insulin secretion. This may weaken glycemic control in patients taking saxagliptin-metformin, and glucose may fall again once phenytoin is stopped.
How serious is the interaction between Fosphenytoin 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 after starting, changing or stopping fosphenytoin and adjust antidiabetic therapy as needed. Watch for hypoglycemia when phenytoin is withdrawn.
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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