- Metabolism: Primarily hepatic (mainly via cytochrome P450 isozyme 2C9), paramethadione is completely demethylated to 5-ethyl-5-methyl-2,4-oxazolidinedione, the active metabolite. Half Life: 12 to 24 hours (however the half-life for the active metabolite is not known)
- Uses/Sources: Used for the control of absence (petit mal) seizures that are refractory to treatment with other medications.
- Health Effects: May cause a potentially dangerous rash that may develop into Stevens Johnson syndrome, an extremely rare but potentially fatal skin disease.
- Symptoms: Symptoms of overdose include clumsiness or unsteadiness, coma, severe dizziness, severe drowsiness, severe nausea, and problems with vision. May cause a potentially dangerous rash that may develop into Stevens Johnson syndrome, an extremely rare but potentially fatal skin disease.
- Route of Exposure: Rapid via the digestive tract.
Mechanism of Action
|Target Name||Mechanism of Action||References|
|Voltage-dependent T-type calcium channel subunit alpha-1I||Dione anticonvulsants such as paramethadione reduce T-type calcium currents in thalamic neurons (including thalamic relay neurons). This inhibits corticothalamic transmission and raises the threshold for repetitive activity in the thalamus. This results in a dampening of the abnormal thalamocortical rhythmicity proposed to underlie the 3-Hz spike-and-wave discharge seen on electroencephalogram (EEG) during absence seizures.||