From the Guidelines
Dilantin (phenytoin) is primarily used to treat and prevent seizures in epilepsy, particularly for tonic-clonic (grand mal) seizures and complex partial seizures.
Key Points
- It works as an anticonvulsant medication by stabilizing electrical activity in the brain, specifically by blocking sodium channels in neurons which prevents them from firing rapidly and excessively 1.
- The typical adult maintenance dose ranges from 300-400 mg daily, often divided into multiple doses.
- Dilantin requires careful monitoring as it has a narrow therapeutic window, meaning blood levels must be maintained within a specific range (10-20 mcg/mL) for effectiveness while avoiding toxicity.
- Common side effects include gingival hyperplasia (gum overgrowth), coordination problems, slurred speech, skin rashes, and cognitive effects.
- Long-term use may lead to vitamin D deficiency, osteoporosis, and peripheral neuropathy.
- Patients should maintain good oral hygiene and have regular dental check-ups while taking this medication.
Administration
- The loading dose for phenytoin is 20 mg/kg divided in maximum doses of 400 mg every 2 h orally, or 18 mg/kg IV at maximum rate of 50 mg/min 1.
- IV administration is faster to load but may have more serious adverse effects than oral administration, including hypotension, bradyarrhythmias, cardiac arrest, and extravasation injuries.
Comparison with Other Medications
- Phenytoin is sometimes compared to other antiepileptic medications like valproate, levetiracetam, and phenobarbital in terms of efficacy and safety for treating seizures and status epilepticus 1.
- The choice of medication often depends on the specific type of seizure, patient factors, and potential side effects.
From the FDA Drug Label
DILANTIN is a prescription medicine used to treat tonic-clonic (grand mal), complex partial (psychomotor or temporal lobe) seizures, and to prevent and treat seizures that happen during or after brain surgery. Dilantin is indicated for the control of generalized tonic-clonic (grand mal) and complex partial (psychomotor, temporal lobe) seizures and prevention and treatment of seizures occurring during or following neurosurgery.
Dilantin (phenytoin) is used for:
- Treating tonic-clonic (grand mal) seizures
- Treating complex partial (psychomotor or temporal lobe) seizures
- Preventing and treating seizures that happen during or after brain surgery 2 2
From the Research
Overview of Dilantin (Phenytoin)
- Dilantin, also known as phenytoin, is an anti-seizure medication used to treat epilepsy 3, 4.
- It is a sodium channel blocker, which means it works by blocking the sodium channels in the brain to prevent seizures 3.
Uses of Phenytoin
- Phenytoin is used to treat various types of seizures, including focal and generalized tonic-clonic seizures 3.
- It is also used to prevent seizures in patients with a history of seizures 5, 6.
- In addition to its use in epilepsy, phenytoin has been evaluated for its potential use in other conditions, although its primary indication remains epilepsy 4.
Important Considerations
- Phenytoin has a narrow therapeutic index, which means that the difference between the effective dose and the toxic dose is small 6, 4.
- Switching between generic versions of phenytoin can lead to changes in serum concentrations and increase the risk of breakthrough seizures 6.
- Patients taking phenytoin should be monitored regularly for signs of toxicity and have their serum concentrations checked regularly 6, 4.