Femitin

Indications

Phenytoin Sodium is an anti-seizure (anti-epileptic) medicine. It is used to control several types of epilepsy, including tonic-clonic (grand mal) seizures and focal seizures, and to prevent or treat seizures during or after brain surgery or head injury. The injection is used in hospital to stop prolonged seizures (status epilepticus).

How It Works

Seizures happen when nerve cells in the brain fire too quickly and spread electrical activity. Phenytoin blocks sodium channels on nerve cells, making them less able to fire repeatedly, which helps stop the spread of seizure activity.

Dosage and Administration

The dose is set by the doctor for each person and adjusted using blood level tests, so take it exactly as prescribed. Small dose changes can cause large changes in blood level. Take it at the same times each day, with or without food but consistently. Swallow capsules whole. Do not stop suddenly, as this can trigger severe seizures. Do not switch brands or between capsules and suspension without your doctor's advice. Injections are given slowly into a vein by a doctor or nurse with heart monitoring.

Interactions

Phenytoin has many interactions. Its level can be raised by Isoniazid, Fluconazole, Amiodarone, Omeprazole, Chloramphenicol, Valproate and alcohol binge, and lowered by Carbamazepine, Rifampicin, regular heavy alcohol use and some antacids. Phenytoin reduces the effect of hormonal contraceptives, Warfarin (effect can change either way), Corticosteroids, Doxycycline, many HIV medicines and others. Enteral tube feeds reduce its absorption. Tell your doctor about every medicine you take.

Contraindications

• Allergy to phenytoin or other hydantoins
• Injection: slow heart rate, heart block or Adams-Stokes attacks
• Use with Delavirdine

Side Effects

Common effects include dizziness, unsteadiness, slurred speech, drowsiness, nausea, constipation, overgrowth of the gums, coarse facial features and increased body hair. Long term use can lower vitamin D and folate and weaken bones. Some people develop low mood.

Get urgent medical help for a rash with fever, blisters or peeling skin, mouth sores, swollen glands, yellow skin or eyes, unusual bruising or bleeding, severe unsteadiness or confusion, thoughts of self-harm, or seizures that do not stop.

Pregnancy and Lactation

Phenytoin can cause birth defects (fetal hydantoin syndrome), but uncontrolled seizures are also dangerous. Do not stop it on your own; plan pregnancy with your doctor, use reliable contraception that is not weakened by phenytoin, and take folic acid as advised. Small amounts pass into breast milk; most mothers can breastfeed with the baby watched for drowsiness, but ask your doctor.

Precautions and Warnings

Regular blood level, blood count and liver checks may be needed. Care is needed in liver disease, diabetes, porphyria and in older people. People of Asian origin with the HLA-B*1502 gene have a higher risk of serious skin reactions. Keep teeth and gums clean. Avoid alcohol. Do not drive until your seizures are controlled and you know how it affects you.

Overdose

Overdose causes jerky eye movements, unsteady walk, slurred speech, confusion, low blood pressure and coma. Seek emergency help at once.

Therapeutic Class

Anti-epileptic (hydantoin)

Storage

Store below 30°C in a dry place, away from light and out of the reach of children. Do not freeze the suspension. Injections are stored as directed on the pack.