Drug interactions
Dronabinol + Phenytoin
Severity: Moderate
Dronabinol 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 dronabinol levels and effect through enzyme induction. Dronabinol is highly protein bound and could theoretically raise free phenytoin, but this is of uncertain clinical importance.
What this interaction means in plain words
Dronabinol 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.
Dronabinol belongs to Central Nervous System; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP2C9 and CYP3A4, increasing dronabinol metabolism; protein-binding displacement of phenytoin is theoretical.
What to do
Monitor for reduced antiemetic or appetite effect and titrate dronabinol upward as needed. Watch for phenytoin toxicity and consider checking free phenytoin levels.
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 Dronabinol
- Cefotetan + Dronabinol Contraindicated
- Disulfiram + Dronabinol Contraindicated
- Dronabinol + Midazolam intranasal Major
- Dronabinol + Zuranolone Major
- Amobarbital + Dronabinol Moderate
- Apalutamide + Dronabinol Moderate
Frequently asked questions
Can I take Dronabinol with Phenytoin?
MediHelp rates the interaction as moderate. Dronabinol 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 dronabinol levels and effect through enzyme induction. Dronabinol is highly protein bound and could theoretically raise free phenytoin, but this is of uncertain clinical importance.
How serious is the interaction between Dronabinol 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 for reduced antiemetic or appetite effect and titrate dronabinol upward as needed. Watch for phenytoin toxicity and consider checking free phenytoin levels.
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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