Drug interactions
Naloxegol + Phenytoin
Severity: Moderate
Naloxegol 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 lower naloxegol concentrations and reduce relief of opioid-induced constipation.
What this interaction means in plain words
Naloxegol 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.
Naloxegol belongs to Gastrointestinal Tract; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4 and P-glycoprotein, increasing naloxegol clearance.
What to do
Avoid the combination; use another laxative or peripherally acting agent such as methylnaltrexone. Monitor bowel response.
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 Naloxegol
- Clarithromycin + Naloxegol Contraindicated
- Itraconazole + Naloxegol Contraindicated
- Ketoconazole + Naloxegol Contraindicated
- Naloxegol + Posaconazole Contraindicated
- Naloxegol + Voriconazole Contraindicated
- Bupropion-naltrexone + Naloxegol Major
Frequently asked questions
Can I take Naloxegol with Phenytoin?
MediHelp rates the interaction as moderate. Naloxegol 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 lower naloxegol concentrations and reduce relief of opioid-induced constipation.
How serious is the interaction between Naloxegol 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: Avoid the combination; use another laxative or peripherally acting agent such as methylnaltrexone. Monitor bowel response.
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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