Drug interactions
Dronabinol + Fosphenytoin
Severity: Moderate
Dronabinol and Fosphenytoin: 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 is converted to phenytoin, which induces CYP3A4 and CYP2C9, the main enzymes metabolizing dronabinol. Dronabinol exposure may fall and its effect may be reduced.
What this interaction means in plain words
Dronabinol and Fosphenytoin 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; Fosphenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induction of CYP2C9 and CYP3A4 increases dronabinol clearance.
What to do
Monitor dronabinol efficacy and increase the dose if needed. Reassess if fosphenytoin is discontinued.
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 Dronabinol
- Cefotetan + Dronabinol Contraindicated
- Disulfiram + Dronabinol Contraindicated
- Dronabinol + Midazolam intranasal Major
- Dronabinol + Zuranolone Major
- Amobarbital + Dronabinol Moderate
- Apalutamide + Dronabinol Moderate
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 Dronabinol with Fosphenytoin?
MediHelp rates the interaction as moderate. Dronabinol and Fosphenytoin 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 is converted to phenytoin, which induces CYP3A4 and CYP2C9, the main enzymes metabolizing dronabinol. Dronabinol exposure may fall and its effect may be reduced.
How serious is the interaction between Dronabinol and Fosphenytoin?
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 dronabinol efficacy and increase the dose if needed. Reassess if fosphenytoin is discontinued.
What other medicines interact with Dronabinol?
MediHelp also lists interactions of Dronabinol with, for example, Cefotetan, Disulfiram, Midazolam intranasal. The full list is on the Dronabinol page.
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