Skip navigation
MedlinePlus Trusted Health Information for You U.S. National Library of MedicineNational Institutes of Health
Contact Us FAQs Site Map About MedlinePlus
español Home Health Topics Drug Information Medical Encyclopedia Dictionary News Directories Other Resources

Other drug names:  A-Am  An-Az  B  C-Ch  Ci-Cz  D-Dh  Di-Dz  E  F  G  H  I-J  K-L  M-Mh  Mi-Mz  N-Nh  Ni-Nz  O  P-Pl  Pm-Pz  Q-R  S-Sn  So-Sz  T-To  Tp-Tz  U-V  W-Z  0-9

Anticonvulsants, Hydantoin  (Systemic)

Printer-friendly versionE-mail this page to a friend
Contents of this page:

Brand Names

Some commonly used brand names are:

In the U.S.—

  • Cerebyx2
  • Dilantin4
  • Dilantin-1254
  • Dilantin Infatabs4
  • Dilantin Kapseals4
  • Mesantoin3
  • Peganone1
  • Phenytek4

In Canada—

  • Cerebyx2
  • Dilantin4
  • Dilantin-304
  • Dilantin-1254
  • Dilantin Infatabs4

Note:

For quick reference, the following hydantoin anticonvulsants are numbered to match the corresponding brand names.

Another commonly used name for phenytoin is diphenylhydantoin.

This information applies to the following medicines:
1.  Ethotoin (ETH-oh-toyn)
2.  Fosphenytoin (fos-FEN-i-toyn)
3.  Mephenytoin (me-FEN-i-toyn)
4.  Phenytoin (FEN-i-toyn)
‡  Generic name product may be available in the U.S.
§  Generic name product may be available in Canada
*  Not commercially available in the U.S.
†  Not commercially available in Canada

Category


Description

Hydantoin anticonvulsants (hye-DAN-toyn an-tye-kon-VUL-sants ) are used most often to control certain convulsions or seizures in the treatment of epilepsy. Phenytoin also may be used for other conditions as determined by your doctor.

In seizure disorders, these medicines act on the central nervous system (CNS) to reduce the number and severity of seizures. Hydantoin anticonvulsants may also produce some unwanted effects. These depend on the patient's individual condition, the amount of medicine taken, and how long it has been taken. It is important that you know what the side effects are and when to call your doctor if they occur.

Hydantoin anticonvulsants are available only with your doctor's prescription, in the following dosage forms:

Because fosphenytoin is converted to phenytoin in your body, it has the same effects as those listed for phenytoin in the following sections.


Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For hydantoin anticonvulsants, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to any hydantoin anticonvulsant medicine. Also tell your health care professional if you are allergic to any other substance, such as foods, preservatives, or dyes.

Pregnancy—Although most mothers who take medicine for seizure control deliver normal babies, there have been reports of increased birth defects when these medicines were used during pregnancy. It is not definitely known if any of these medicines are the cause of such problems.

Also, pregnancy may cause a change in the way hydantoin anticonvulsants are absorbed in your body. You may have more seizures, even though you are taking your medicine regularly. Your doctor may need to increase the anticonvulsant dose during your pregnancy.

In addition, when taken during pregnancy, this medicine may cause a bleeding problem in the mother during delivery and in the newborn. This may be prevented by giving vitamin K to the mother during delivery, and to the baby immediately after birth.

Breast-feeding—Ethotoin and phenytoin pass into the breast milk in small amounts. It is not known whether mephenytoin passes into breast milk. Be sure you have discussed the risks and benefits of the medicine with your doctor.

Children—Some side effects, especially bleeding, tender, or enlarged gums and enlarged facial features, are more likely to occur in children and young adults. Also, unusual and excessive hair growth may occur, which is more noticeable in young girls. In addition, some children may not do as well in school after using high doses of this medicine for a long time.

Older adults—Some medicines may affect older patients differently than they do younger patients. Overdose is more likely to occur in elderly patients and in patients with liver disease.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking or receiving hydantoin anticonvulsants, it is especially important that your health care professional know if you are taking any of the following:

Other medical problems—The presence of other medical problems may affect the use of hydantoin anticonvulsants. Make sure you tell your doctor if you have any other medical problems, especially:


Proper Use of This Medicine

For patients taking the liquid form of this medicine:

For patients taking the chewable tablet form of this medicine:

For patients taking the capsule form of this medicine:

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 .

Missed dose—

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

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

Storage—

To store this medicine:


Precautions While Using This Medicine

Your doctor should check your progress at regular visits, especially during the first few months of treatment with this medicine. During this time the amount of medicine you are taking may have to be changed often to meet your individual needs.

Do not start or stop taking any other medicine without your doctor's advice. Other medicines may affect the way this medicine works .

This medicine will add to the effects of alcohol and other CNS depressants (medicines that may make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; other medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine.

Do not take this medicine within 2 to 3 hours of taking antacids or medicine for diarrhea. Taking these medicines and hydantoin anticonvulsants too close together may make the hydantoins less effective.

Do not change brands or dosage forms of phenytoin without first checking with your doctor. Different products may not work the same way. If you refill your medicine and it looks different, check with your pharmacist.

If you have been taking this medicine regularly for several weeks or more, do not suddenly stop taking it. Your doctor may want you to reduce gradually the amount you are taking before stopping completely.

Your doctor may want you to carry a medical identification card or bracelet stating that you are taking this medicine.

For diabetic patients:

Before you have any medical tests, tell the doctor in charge that you are taking this medicine. The results of some tests (including the dexamethasone, metyrapone, or Schilling tests, and certain thyroid function tests) may be affected by this medicine.

Before having any kind of surgery, dental treatment, or emergency treatment, tell the medical doctor or dentist in charge that you are taking this medicine. Taking hydantoin anticonvulsants together with medicines that are used during surgery or dental or emergency treatments may cause increased side effects.

This medicine may cause some people to become dizzy, lightheaded, drowsy, or less alert than they are normally. After you have taken this medicine for a while, this effect may not be so bothersome. However, make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert .

Oral contraceptives (birth control pills) containing estrogen or progestin, contraceptive progestin injections (e.g., Depo-Provera), and implant contraceptive forms of progestin (e.g., Norplant) may not work properly if you take them while you are taking hydantoin anticonvulsants. Unplanned pregnancies may occur. You should use a different or additional means of birth control while you are taking hydantoin anticonvulsants. If you have any questions about this, check with your health care professional.

For patients taking phenytoin or mephenytoin:


Side Effects of This Medicine

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects or signs of overdose occur:

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.


Additional Information

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, phenytoin is used in certain patients with the following medical conditions:

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.

Revised: 05/01/2000

Micromedex, Inc. Disclaimer

Copyright© 2003 Thomson MICROMEDEX. All rights reserved. USP DI® and Advice for the Patient® are registered trademarks of USP used under license to Micromedex, a business of Thomson Healthcare Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes.