Phenytoin

Composition:
Each extended contains:
Phenytoin Sodium                  50 mg

Pharmacological Properties:
Phenytoin is an antiepileptic (anticonvulsant) drug which is useful in the treatment of status epilepticus of grand mal type. Phenytoin acts to stabilize the threshold against hyperexcitability. Phenytoin reduces the maximal activity of brain stem centers resposible for the tonic phase of tonic-colonic (grand mal) seizures.

Pharmacokinetics:
The plasma half-life in man after oral administration of extended capsules ranges from 7 to 42 hours. Serum level determinations should be obtained at least 5-7 half-lives after treatment initation. Optimum control without clinical signs of toxicity occurs more often with serum levels between 10 and 20 µg/ml. Phenytoin is highly protein bound. There may be wide interpatient variability in phenytoin serum levels with equivalent dosages due to liver disease, congenital enzyme dificiency or hyper metabolizers of phenytoin.

Indications:
Phenytoin 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.

Contraindications:
This medications is contraindicated in case of hypersensitivity to phenytoin or other hydantoins, sinus bradycardia, sino-atrial block, second and third degree A-V block.

Warnings:
•    Gradual withdrawal of phenytoin should be done, however, in the event of an allergic reaction, rapid substitution of an antiepileptic drug not belonging to the hydantoin class.
•    Phenytoin should be used with caution in patients with hypotension and servere myocardial insufficiency.

Pregnancy and lacation:
Phenytoin sodium is not recommended in pregnant and lactating women.

Precautions:
Osteomalacia and hyperglycemia have been associated with phenytoin therapy.

Drug interactions:
1- Drugs which may increase phenytoin serum levels such as chloramphenicol, cimetidine, diazepam, disulfiram, estrogens, salicylates and sulfonamides.
2- Drugs which may increase phenytoin serum levels such as carbamazepine and sucralfate.
3- Drugs whose efficacy is impaired by phenytoin include corticosteroids, coumarin anticoagulants, vitamin D and furosemide.

Side effects:
The common side effects include ataxia, mental confusion, insomnia, nausea constipation, slurred speech and measles like rash.

Dosage and administration:
Dosage should be individualized to provide maximum benefit. With recommended dosage, a peroid of seven to ten days may be required to achieve steady-state blood levels of phenytoin.

Status Epilepticus:
Adults:
100 gm. Three times daily, then the doage adjusted according to individual requirements.
Neonates and children:
A loading dose of 15 –20 mg/kg, should be administered slowly intravenously  not exceeding 1-3 mg/kg/min.
Continuous monitoring of the electrocardiagram and blood pressure is essential


Storage:
Store below 30°C, protect from light and moisture
 
Packing: