Phenytoin: What is it and what is it for?

What is phenytoin?

Phenytoin or diphenylhydantoin, is a synthetic medicine classified as an active ingredient, which belongs to the line of antiepileptic and anticonvulsant drugs, with effect on the central nervous system (CNS) to treat some imbalances derived from involuntary electrical alterations in thebrain. (1)

What is phenytoin for?

• Thanks to its mechanism of action, phenytoin inhibits the release of voltage-gated excitatoryneurotransmitters, preventing the involuntary manifestationof electrical shocks that cause epileptic states.
• It is used to treat:
  • Generalized tonic-clonic seizures (grand mal) and complex partial seizures. (2)
  • Attacks occurring during or following neurosurgical events (Prevention).
  • Migraine, trigeminal neuralgia and certain psychoses.
  • Cardiac arrhythmias, digitalis poisoning and aftertreatment inmyocardial infarction.

Dosage and routes of administration of phenytoin

Phenytoin comes as a100 mg sodium phenytoin tablet or a phenytoinsodium 250 mg solution for injection. The route of administration is according to the presentation, being oral andintravenous or intramuscular respectively andthe dosage may be as follows:

• Tablets: Adults, initial treatment of 300 mg in three doses of 100 mg per day and then adjusted, until plasma levels between 10 and 20 mcg / ml are reached. For pediatric use, a dose of 5 mg/kg/day in 2 or 3 equal divided doses is recommended.
• Solution: In adults up to 50 mg per minute. In the case of using the infusion method, it should not exceed a final concentration of 10 mg / ml, however consultation and medical supervision is recommended during administration.

What products contain phenytoin?

Some of the medicines that contain phenytoin are:

• Dilantin®
• Epamin®
• Epamin SP®

Dilantin®

• Dilantin is a synthetic pharmaceutical product whose active substance is phenytoin.®
• It is used to treat or preventseizures that epilepsy can cause.

Epamin®

• Epamin is a medicinethat uses phenytoin® as the active substance, which comes in the form of 100 mg tablets.
• It is used toinhibit the spread of convulsive activityin the cerebral motor cortex.

Epamin SP®

• Epamin sp®is a chemical compound in the form of a solution for injection, which uses phenytoin sodium 250 mg as the active ingredient.
• It is used to treattonic-clonic seizures, migraine, neuralgia and cardiac arrhythmias.

Phenytoin Side Effects

Clinical evidence suggests that drug treatment with phenytoin may cause some of the following adverse effects in a certain patient population:

• Possible allergic reactions due to contact with any component of the formula.
• Ataxia, confused language, decreased coordination and mental confusion.
• Vertigo, insomnia, transient nervousness, motor spasm, headache, paresthesia and drowsiness.
• Peripheral polyneuropathy predominantly sensory.
• Thickening of the lips, gingival hyperplasia, hypertrichosis andPeyronie’s disease.
• Megaloblastic anemiaand liver failure.
• Nausea, vomiting, constipation, toxic hepatitis and liver damage.
• Thrombocytopenia, leukopenia, granulocytopenia, agranulocytosis and pancytopenia in the bone marrow.
• Systemic lupus erythematosus and periarteritis nodosa.
• Additionally in the case of injections local irritation, inflammation, sensitivity, necrosis and gangrene.

Important: If any of these or other symptoms appear not listed, pleasediscontinue use and notify your doctor.

Contraindications and warnings of phenytoin

The use of phenytoinis contraindicatedin the following cases:

• Patients with hypersensitivity to any of the components of the formula.
• People with severe coronary heart disease.
• Patients with small epileptic disease.
• Patients withAdams-Stokes syndrome.
• During the period of pregnancy.
• Duringbreastfeeding.

To highlight: Before starting treatment with this medicine, giveall information about your health history to yourdoctor.

Avoid it if you have:

• History of hypersensitivity to phenytoin or other hydantoins.
• History of coronary heart disease.

Warnings:

• Pharmaceuticals, such as phenytoin, must be administered with a prescription or prescription.
• This is one of the medications considered psychotropic, so you should strictly follow your doctor’s instructions.
• Phenytoin should not be administered concomitantly with other medicines such ascarbamazepine,diazepam,fluconazole, vitamin D or vitaminKdeficiency and in general drugs for other pathologies, without medical authorization.
• The administration of this drug should not be abruptly discontinued, due to the risk of increased epileptic seizures.
• Do not administer this medicine during the consumption of alcoholic beverages.
• Keep this product out of reach of children.
• Do not alter the dose indicated by your doctor, to avoid the development of severe side effects.