Trimethadione

Trimethadione is a prescription medication used to treat absence (petit mal) seizures that are not controlled with other drugs. Trimethadione belongs to a group of drugs called antiepileptics, which work by decreasing abnormal electrical activity in the brain.

This medication comes in a chewable tablet form and is taken 3 or 4 times a day, with or without food.

Common side effects of trimethadione include nausea, changes in behavior, and drowsiness. Trimethadione can also cause blurred vision. Do not drive or operate heavy machinery until you know how trimethadione affects you.

Trimethadione is a prescription medication used to treat absence (petit mal) seizures that are not controlled with other drugs.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Take trimethadione exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The trimethadione dose your doctor recommends will be based on the following:

• the condition being treated
• other medical conditions you have
• how you respond to this medication

The recommended dose range for trimethadione in adults is 300 to 600 mg, three or four times a day.

The recommended dose range for trimethadione in children is 100 to 300 mg, three or four times a day.

Trimethadione can cause serious side effects, including:

1. Rash. This may need to be treated in a hospital and may be life-threatening. Call your healthcare provider right away if you have any of these symptoms:

• skin rash
• hives
• sores in your mouth

2. Blood problems that can be life-threatening. Call your healthcare provider right away if you have any of these symptoms:

• Fever, swollen glands, or sore throat that come and go or do not go away
• Frequent infections or an infection that does not go away
• Easy bruising
• Red or purple spots on your body
• Bleeding gums or nose bleeds
• Severe fatigue or weakness

3. Liver problems. Call your healthcare provider right away if you have any of these symptoms:

• yellowing of your skin or the whites of your eyes (jaundice)
• dark urine
• nausea or vomiting
• loss of appetite
• pain on the right side of your stomach (abdomen)

4. Kidney problems that may be life-threatening.

5. Eye problems. Call your healthcare provider right away if you have any new changes in your vision such as:

• problems seeing in bright light
• blurred vision

6. Birth defects in your unborn baby.

• Women who can become pregnant should talk to their healthcare provider about using other possible treatments instead of trimethadione. If the decision is made to use trimethadione, women should use effective birth control (contraception). Talk with your healthcare provider if you are pregnant or plan to become pregnant. Birth defects may occur even in children born to women who are not taking any medicines and do not have other risk factors.
• Tell your healthcare provider right away if you become pregnant while taking trimethadione. You and your healthcare provider should decide if you will continue to take trimethadione while you are pregnant.
• If you become pregnant while taking trimethadione, talk to your healthcare provider about registering with the North American Antiepileptic Drug Pregnancy Registry. You can enroll in this registry by calling 1-888-233-2334. The purpose of this registry is to collect information about the safety of antiepileptic drugs during pregnancy.
• Tell your healthcare provider right away if you are breastfeeding or plan to breastfeed. It is unknown if trimethadione passes into breast milk. Talk to your healthcare provider about the best way to feed your baby if you take trimethadione.

7. Like other antiepileptic drugs, trimethadione may cause suicidal thoughts or actions in a very small number of people, about 1 in 500. Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:

• thoughts about suicide or dying
• attempts to commit suicide
• new or worse depression
• new or worse anxiety
• feeling agitated or restless
• panic attacks
• trouble sleeping (insomnia)
• new or worse irritability
• acting aggressive, being angry, or violent
• acting on dangerous impulses
• an extreme increase in activity and talking (mania)
• other unusual changes in behavior or mood

How can I watch for early symptoms of suicidal thoughts and actions?

• Pay attention to any changes, especially sudden changes in mood, behaviors, thoughts, or feelings.
• Keep all follow-up visits with your healthcare provider as scheduled.
• Call your healthcare provider between visits as needed, especially if you are worried about symptoms.

8. Symptoms that are like the symptoms of lupus or myasthenia gravis. Call your healthcare provider right away if you have any of these symptoms:

• droopy eyelids
• a rash on your cheeks or other parts of your body
• sensitivity to the sun
• new joint or muscle pains
• chest pain or shortness of breath
• swelling of your feet, ankles, and legs
• weakness of your arms or legs
• problems swallowing
• speech problems
• swollen glands (enlarged lymph nodes)

Trimethadione can cause blurred vision and drowsiness. Do not drive or operate heavy machinery until you know how trimethadione affects you.

Do not stop trimethadione without first talking to a healthcare provider. Stopping trimethadione suddenly can cause serious problems. Stopping a seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus).

Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes.

Do not take trimethadione if you are allergic to trimethadione or to any of its ingredients.

Serious side effects have been reported with trimethadione. See the “Drug Precautions” section.

Common side effects of trimethadione include the following:

• nausea
• sleepiness
• tiredness
• increase in seizures
• feelings of anger and frustration
• changes in behavior

This is not a complete list of trimethadione side effects. Ask your doctor or pharmacist for more information.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

No trimethadione drug interactions have been identified except an interaction with alcohol. You should tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Not all drug interactions are known or reported and new drug interactions are continually being reported.

Tell your doctor if you are pregnant or plan to become pregnant.

Women who become pregnant are encouraged to enroll in the NAAED Pregnancy Registry. This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll free number 1-888-233-2334.

See the section “Trimethadione Precautions” for more information regarding use of trimethadione during pregnancy.

Tell your doctor if you are breastfeeding or plan to breastfeed.

It is not known if trimethadione crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using trimethadione.

Trimethadione taken with alcohol or drugs that cause sleepiness or dizziness may make your sleepiness or dizziness worse.

Do not drive, operate heavy machinery, or do other dangerous activities until you know how trimethadione affects you. Trimethadione can slow your thinking and motor skills.

Do not stop taking trimethadione without talking to your healthcare provider. Stopping trimethadione suddenly can cause serious problems, including seizures that will not stop (status epilepticus).

Like other antiepileptic drugs, trimethadione may cause suicidal thoughts or actions. Pay attention to any changes, especially sudden changes in mood, behaviors, thoughts, or feelings.

Tell your healthcare provider right away if you become pregnant while taking trimethadione. You and your healthcare provider should decide if you will continue to take trimethadione while you are pregnant.