Anticonvulsants, Hydantoin (Systemic)

Proper Use of This Medicine

For patients taking the liquid form of this medicine:

• Shake the bottle well before using.
• Use a specially marked measuring spoon, a plastic syringe, or a small measuring cup to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

For patients taking the chewable tablet form of this medicine:

• Tablets may be chewed or crushed before they are swallowed, or may be swallowed whole.

For patients taking the capsule form of this medicine:

• Swallow the capsule whole.

If this medicine upsets your stomach, take it with food, unless otherwise directed by your doctor. The medicine should always be taken at the same time in relation to meals to make sure that it is absorbed in the same way.

To control your medical problem, take this medicine every day exactly as ordered by your doctor. Do not take more or less of it than your doctor ordered. To help you remember to take the medicine at the correct times, try to get into the habit of taking it at the same time each day.

Dosing - The dose of hydantoin anticonvulsants will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of ethotoin, fosphenytoin, mephenytoin, and phenytoin. If your dose is different, do not change it unless your doctor tells you to do so.

The number of capsules or tablets or teaspoonfuls of suspension that you take or the number of injections you receive depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using a hydantoin anticonvulsant .

For ethotoin
• For oral dosage form (tablets):
  • As an anticonvulsant:
    • Adults and teenagers - To start, 125 to 250 milligrams (mg) four to six times a day. Your doctor may increase your dose gradually over several days if needed. However, the dose is usually not more than 3000 mg a day.
    • Children - To start, up to 750 mg a day, based on the age and weight of the child. The doctor may increase the dose gradually if needed.

For fosphenytoin
• For injection dosage form:
  • As an anticonvulsant:
    • Adults and children - Dose is based on the illness being treated, and the body weight or size of the patient. The medicine is injected into a vein or muscle.

For mephenytoin
• For oral dosage form (tablets):
  • As an anticonvulsant:
    • Adults and teenagers - To start, 50 to 100 milligrams (mg) once a day. Your doctor may increase your dose by 50 to 100 mg a day at weekly intervals if needed. However, the dose is usually not more than 1200 mg a day.
    • Children - To start, 25 to 50 mg once a day. The doctor may increase the dose by 25 to 50 mg a day at weekly intervals if needed. However, the dose is usually not more than 400 mg a day.

For phenytoin
• For oral dosage forms (capsules, chewable tablets, or suspension):
  • As an anticonvulsant:
    • Adults and teenagers - To start, 100 to 125 milligrams (mg) three times a day. Your doctor may adjust your dose at intervals of seven to ten days if needed.
    • Children - Dose is based on body weight or body surface area. The usual dose is 5 mg of phenytoin per kilogram (kg) (2.3 mg per pound) of body weight to start. The doctor may adjust the dose if needed.
    • Older adults - Dose is based on body weight. The usual dose is 3 mg per kg (1.4 mg per pound) of body weight. The doctor may need to adjust the dose based on your response to the medicine.
• For injection dosage form:
  • As an anticonvulsant:
    • Adults and children - Dose is based on the illness being treated, and the body weight or size of the patient. The medicine is usually injected into a vein.

Missed dose - If you miss a dose of this medicine and your dosing schedule is:

• One dose a day - Take the missed dose as soon as possible. However, if you do not remember the missed dose until the next day, skip it and go back to your regular dosing schedule. Do not double doses.
• More than one dose a day - Take the missed dose as soon as possible. However, if it is within 4 hours of your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

If you miss doses for 2 or more days in a row, check with your doctor.

Storage - To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Keep the liquid form of this medicine from freezing. Do not refrigerate.
• Do not keep outdated medicine or medicine no longer needed. Be sure any discarded medicine is out of the reach of children.