Trimethadione
Trimethadione is an anticonvulsant medication primarily used to treat absence seizures (petit mal seizures) in patients who have not responded to other treatments. It belongs to the oxazolidinedione class of anti-epileptic drugs and is typically reserved for specific seizure disorders due to its side effect profile.
An older anticonvulsant medication for absence seizures when other treatments have failed.
Key facts at a glance
- ATC
- N03AC02
- RxNorm
- 10827
- Generic
- Trimethadione
- Class
- atc-n03
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet, capsule
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Primarily used for absence seizures (petit mal epilepsy) that have not responded adequately to other anti-epileptic medications. May also be used for other types of refractory seizures in some cases.
The exact mechanism is not fully understood, but trimethadione is believed to reduce abnormal electrical activity in the brain by affecting sodium and calcium channels in neurons, helping to stabilize neural membranes and prevent seizure activity.
May cause significant side effects including drowsiness, dizziness, visual disturbances, and blood disorders. Requires regular monitoring of blood counts and liver function. Use during pregnancy may cause fetal harm. Not typically used as a first-line treatment due to its side effect profile.
Official drug label
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This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy