Often used for:
Seizure prevention and treatment, migraines, nerve pain
What is phenytoin?
Phenytoin is an anticonvulsant that helps prevent or control seizures and may be used for migraines or nerve pain. Oral forms include suspension, capsules, and chewable tablets; the injectable form is fosphenytoin.
Phenytoin at home
- Take exactly as prescribed at the same times daily.
- Follow missed-dose instructions provided by the care team.
- Store medicine at room temperature.
Possible side effects
- Nausea or vomiting
- Drowsiness or dizziness
- Allergic reactions (rash, hives, itching, chills, fever, headache, muscle ache, shortness of breath, coughing, tightness in the throat, swelling of the face or neck)
- Late effects include gum changes, blurred or double vision, decreased coordination, nervousness, muscle twitching, slurred speech, headache, increased hair growth, skin rash, easy bruising, high blood sugar, low blood counts, sleep problems, allergic reactions with fever and liver changes
- Not all patients experience these effects. Report any symptoms.
Tips for patients and families
- Blood levels are checked regularly; draw blood just before the next dose unless otherwise instructed.
- Report symptoms such as blurred vision, coordination changes, vomiting, or increased drowsiness; these may indicate high levels.
- Do not stop phenytoin abruptly; seizure risk increases.
- Store at room temperature.
- Use caution with activities requiring alertness until the effects are known.
- Report any rash immediately.
- Maintain consistent dosing to keep blood levels stable.
- Brush, floss, and visit the dentist regularly.
- Discuss all medicines, as many interact with phenytoin.
- Avoid alcohol-containing products that can increase drowsiness.
- Keep follow-up appointments for liver function tests.
