Drug reference
phenytoin
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.
Drug class
Central Nervous System (Anti Epileptic Drugs)
Mechanism of action
Promotes Na+ efflux or decreases Na+ influx from membranes in motor cortex neurons; stabilizes neuronal membrane. Slows conduction velocity
Common side effects
- Restlessness
- Drowsiness
- Headache
- Fatigue
- Ataxia
- Slurred speech
- Irritability
Known interactions (10)
- apixaban + phenytoin Major
- cariprazine + phenytoin Major
- dronedarone + phenytoin Major
- everolimus + phenytoin Major
- fluconazole + phenytoin Major
- phenytoin + trimethoprim-sulfamethoxazole Major
- carbamazepine + phenytoin Moderate
- ciprofloxacin + phenytoin Moderate
- ergotamine + phenytoin Moderate
- erythromycin + phenytoin Moderate
Related conditions
Frequently asked questions
What drug class is phenytoin?
phenytoin belongs to: Central Nervous System.
How does phenytoin work?
Promotes Na+ efflux or decreases Na+ influx from membranes in motor cortex neurons; stabilizes neuronal membrane. Slows conduction velocity
What are the common side effects of phenytoin?
Restlessness, Drowsiness, Headache, Fatigue, Ataxia, Slurred speech, Irritability
Which drugs interact with phenytoin?
apixaban, cariprazine, dronedarone, everolimus, fluconazole, trimethoprim-sulfamethoxazole, carbamazepine, ciprofloxacin, ergotamine, erythromycin
Full monographs, dosing and an interaction checker in the MediHelp app
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