Available Dosage Forms:
- Tablet, Chewable
Therapeutic Class: Anticonvulsant
Chemical Class: Oxazolidinedione
Medically reviewed by Drugs.com. Last updated on Jan 22, 2019.
Uses For trimethadione
Trimethadione is used to control absence (petit mal) seizures in patients with epilepsy who have used other medicines that did not work well. Trimethadione is an anticonvulsant that works in the brain tissue to stop seizures.
Trimethadione is available only with your doctor's prescription.
Before Using trimethadione
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 trimethadione, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to trimethadione or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies on the relationship of age to the effects of trimethadione have not been performed in the pediatric population. However, no pediatric-specific problems have been documented to date.
No information is available on the relationship of age to the effects of trimethadione in geriatric patients.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with 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 trimethadione, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using trimethadione with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of trimethadione. Make sure you tell your doctor if you have any other medical problems, especially:
- Blood disorder, severe or
- Kidney disease, severe or
- Liver disease, severe—Should not be used in patients with these conditions.
- Depression, history of or
- Eye problems—Use with caution. May make these conditions worse.
Proper Use of trimethadione
Take trimethadione only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.
Trimethadione comes with a Medication Guide. Read and follow the instructions carefully. Ask your doctor if you have any questions.
You may chew this tablet or swallow it whole.
The dose of trimethadione 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 trimethadione. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take 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 the medicine.
- For oral dosage form (chewable tablets):
- For seizures:
- Adults—0.9 to 2.4 grams (g) per day in 3 or 4 equally divided doses (eg, 300 to 600 milligrams [mg] tablet 3 or 4 times daily). Your doctor may increase your dose as needed.
- Children—The dose is usually. 0.3 to 0.9 g per day in 3 or 4 equally divided doses.
- For seizures:
If you miss a dose of trimethadione, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store in the refrigerator. Do not freeze.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions While Using trimethadione
It is very important that your doctor check your and your child's progress closely while using trimethadione to see if it is working properly and to allow for a change in the dose. Blood and urine tests may be needed to check for any unwanted effects.
Do not stop taking trimethadione without first checking with your doctor. Stopping a seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus). Your doctor may want you or your child to slowly reduce the amount you are using before stopping completely.
Trimethadione may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you, your child, or your caregiver notice any of these side effects, tell your doctor right away.
Trimethadione may cause lupus-like and myasthenia-like symptoms. Check with your doctor right away if you or your child has droopy eyelids, rash on the cheeks or other parts of the body, sensitivity of the skin to sunlight, joint or muscle pain, chest pain, swelling of the feet, ankles, and legs, weakness of the arms or legs, trouble swallowing, speech problems, or swollen glands.
Tell your doctor right away if you or your child feels unusually weak, starts bruising easily, has bleeding gums or nosebleeds, seems to be sick more often, has a fever, swollen glands, or a sore throat that will not go away. These could be a signs of a serious problem with the number of blood cells in your body.
Serious skin reactions can occur with trimethadione. Check with your doctor right away if you or your child have a severe skin rash, blistering, peeling, or loosening of the skin, red skin lesions, sores or ulcers on the skin, or fever or chills while you or your child are using trimethadione.
Trimethadione may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how trimethadione affects you.
Check with your doctor before using trimethadione with alcohol or other medicines that affect the central nervous system (CNS). The use of alcohol or other medicines that affect the CNS with trimethadione may worsen the side effects of trimethadione, such as dizziness, poor concentration, drowsiness, unusual dreams, and trouble with sleeping. Some examples of medicines that affect the CNS are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicines, medicine for depression, medicine for anxiety, prescription pain medicine or narcotics, medicine for attention deficit and hyperactivity disorder, other medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics.
Trimethadione Side Effects
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 immediately if any of the following side effects occur:
Incidence not known
- Black, tarry stools
- bleeding gums
- blistering, peeling, or loosening of the skin
- blisters, hives, or itching
- blood in the urine or stools
- blurred vision
- changes in blood pressure
- changes in vision, especially night blindness
- chest pain
- cloudy or dark urine
- cracks in the skin
- decreased vision
- difficulty in breathing, chewing, swallowing, or talking
- double vision
- drooping eyelids
- fever with or without chills
- general feeling of discomfort or illness
- general feeling of tiredness or weakness
- glare or snowy image caused by bright light
- hair loss
- high fever
- increased irritability
- increased sensitivity of the eyes to sunlight
- light-colored stools
- loss of bladder control
- loss of heat from the body
- lower back or side pain
- muscle or joint pain
- muscle weakness
- painful or difficult urination
- pale skin
- personality changes
- pinpoint red spots on the skin
- red, irritated eyes
- red, swollen skin
- scaly skin
- severe tiredness
- skin rash
- small red or purple spots on the skin
- sore throat
- sores, ulcers, or white spots in the mouth or on the lips
- swelling of the face, hands, legs, and feet
- swollen, painful, or tender lymph glands in the neck, armpit, or groin
- total body jerking
- unusual bleeding or bruising
- unusual tiredness or weakness
- upper right abdominal pain
- vaginal bleeding
- yellow eyes and skin
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
- Loss of consciousness
- shakiness and unsteady walk
- unsteadiness, trembling, or other problems with muscle control or coordination
Some 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. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Incidence not known
- Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
- dizziness or lightheadedness
- feeling of constant movement of self or surroundings
- loss of appetite
- sensation of spinning
- stomach pain or distress
- trouble sleeping
- weight loss
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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