indication

Used in the control of absence (petit mal) seizures that are refractory to treatment with other medications.

pharmacology

Paramethadione and trimethadione are anticonvulsants indicated in the control of absence (petit mal) seizures that are refractory to treatment with other medications. Dione anticonvulsants are used in the treatment of epilepsy. They act on the central nervous system (CNS) to reduce the number of seizures.

mechanism of action

Dione anticonvulsants reduce T-type calcium currents in thalamic neurons, including thalamic relay neurons. It does so via the inhibition of voltage dependent T-type calcium channels. This raises the threshold for repetitive activity in the thalamus, and inhibits corticothalamic transmission. Thus, the abnormal thalamocortical rhythmicity, which is thought to underlie the 3-Hz spike-and-wave discharge seen on electroencephalogram(EEG) with absence seizures, is dampened.

toxicity

Symptoms of overdose include clumsiness or unsteadiness, coma, dizziness (severe), drowsiness (severe), nausea (severe), and problems with vision.

drug interactions

Disulfiram: Disulfiram, a strong CYP2E1 inhibitor, may decrease the metabolism and clearance of Trimethadione, a CYP2E1 substrate. Consider alternate therapy or monitor for changes in Trimethadione therapeutic and adverse effects if Disulfiram is initiated, discontinued or dose changed.

Triprolidine: The CNS depressants, Triprolidine and Trimethadione, may increase adverse/toxic effects due to additivity. Monitor for increased CNS depressant effects during concomitant therapy.