Methsuximide

Mechanism :

Increases the seizure threshold and suppresses paroxysmal spike-and-wave pattern in absence seizures; depresses nerve transmission in the motor cortex.

Indication :

Refractory Absence seizures

Contraindications :

History of hypersensitivity to succinimides.

Dosing :

>12 years:

Initial: 300 mg/day PO. May increase by 300 mg/week; not to exceed 1.2 g/day in divided doses.

Adverse Effect :

Aggressiveness, ataxia, confusion, depression, dizziness, drowsiness, hallucinations (auditory), headache, hypochondriacal behaviour, insomnia, irritability, Pruritus, rash, Stevens-Johnson syndrome, urticarial, Eosinophilia, leukopenia, monocytosis, Blurred vision, periorbital edema, photophobia, hiccups, systemic lupus erythematosus.

Interaction :

CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants.
CYP2C19 Inducers: May increase the metabolism of CYP2C19 Substrates.
CYP2C19 Inhibitors: May decrease the metabolism of CYP2C19 Substrates.
Mefloquine: May diminish the therapeutic effect of Anticonvulsants.
Opioid Analgesics: CNS Depressants may enhance the CNS depressant effect of Opioid Analgesics.
Selective Serotonin Reuptake Inhibitors: CNS Depressants may enhance the adverse/toxic effect of Selective Serotonin Reuptake Inhibitors.

Hepatic Dose :

Dose adjustment in hepatic impairment: Specific guidelines are not available. Use with caution as methsuximide undergoes significant hepatic metabolism.