- Body system
- Neurology
- Brand names
- Dilantin, Phenytek
- Therapeutic level
- Commonly 10 to 20 mcg/mL (total phenytoin).
What is Phenytoin used for?
- Tonic-clonic and focal seizures
- Status epilepticus (after a benzodiazepine)
- Seizure prevention after neurosurgery
Fosphenytoin (Cerebyx) is an IV and IM prodrug that is converted to phenytoin and is dosed in phenytoin equivalents (PE).
How Phenytoin works
Hydantoin: blocks sodium channels and stabilizes neuron membranes.
Common side effects
- Gingival hyperplasia (gum overgrowth)
- Nystagmus, ataxia, slurred speech and confusion (signs of high levels)
- Hirsutism
- Rash
Report right away
- Any rash, which can progress to Stevens-Johnson syndrome
- Unsteady walking, double vision or confusion
- Seizures that return or change
Nursing considerations for Phenytoin
- Total phenytoin levels are commonly 10 to 20 mcg/mL. Low albumin raises the active free fraction: a free level may be checked.
- IV: give no faster than 50 mg per minute in adults (slower in older adults and children), mix and flush only with normal saline (it precipitates in dextrose), use a filter if required, and monitor the ECG and blood pressure.
- Enteral feedings lower absorption of the suspension: follow the facility's protocol for holding tube feedings around doses. Shake the suspension well.
Patient teaching
- Brush and floss carefully and see the dentist regularly.
- Do not switch brands or stop the drug suddenly.
- It interacts with many drugs and lowers the effect of hormonal contraceptives: use another method.
This card does not list doses. Use the prescriber's order, the product label and a current drug reference for dosing, and follow your facility's policies.
Anticonvulsants (antiepileptic drugs) practice questions
NCLEX-style questions on the class Phenytoin belongs to.
3 questions. Choose an answer to see the rationale.
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Which IV solution is compatible with phenytoin?
Show answer
Answer B: 0.9% sodium chloride Phenytoin precipitates in dextrose solutions; it is mixed and flushed with normal saline only.
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A patient taking phenytoin has nystagmus, unsteady gait and slurred speech. What does the nurse suspect?
Show answer
Answer D: Phenytoin toxicity Nystagmus and ataxia are classic signs of high phenytoin levels. Check the level and notify the provider.
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What teaching point applies to every antiepileptic drug?
Show answer
Answer C: Do not stop it suddenly Abrupt withdrawal can trigger seizures, including status epilepticus.
Frequently asked questions
What is Phenytoin used for?
Tonic-clonic and focal seizures; Status epilepticus (after a benzodiazepine); Seizure prevention after neurosurgery.
What drug class is Phenytoin?
Phenytoin belongs to the class anticonvulsants (antiepileptic drugs). Hydantoin: blocks sodium channels and stabilizes neuron membranes.
What are the nursing considerations for Phenytoin?
Total phenytoin levels are commonly 10 to 20 mcg/mL. Low albumin raises the active free fraction: a free level may be checked. IV: give no faster than 50 mg per minute in adults (slower in older adults and children), mix and flush only with normal saline (it precipitates in dextrose), use a filter if required, and monitor the ECG and blood pressure.
What should patients report while taking Phenytoin?
any rash, which can progress to Stevens-Johnson syndrome; unsteady walking, double vision or confusion; seizures that return or change.