Drug interactions
Fosphenytoin + Zolpidem
Severity: Moderate
Fosphenytoin and Zolpidem: 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
Fosphenytoin, via phenytoin, induces CYP3A4 and may reduce zolpidem concentrations and hypnotic effect. Both also can cause CNS depression.
What this interaction means in plain words
Fosphenytoin and Zolpidem 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; Zolpidem belongs to Central Nervous System.
Why it happens
Phenytoin induction of CYP3A4 increases zolpidem clearance.
What to do
Monitor for loss of hypnotic efficacy and consider an alternative if the response is inadequate. Do not exceed the maximum labeled zolpidem dose.
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 Zolpidem
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 Zolpidem?
MediHelp rates the interaction as moderate. Fosphenytoin and Zolpidem 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, via phenytoin, induces CYP3A4 and may reduce zolpidem concentrations and hypnotic effect. Both also can cause CNS depression.
How serious is the interaction between Fosphenytoin and Zolpidem?
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 for loss of hypnotic efficacy and consider an alternative if the response is inadequate. Do not exceed the maximum labeled zolpidem dose.
What other medicines interact with Zolpidem?
MediHelp also lists interactions of Zolpidem with, for example, Calcium / magnesium / potassium / sodium oxybates, Sodium oxybate, Benzhydrocodone / acetaminophen. The full list is on the Zolpidem page.
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