Zonisamide toxicity

Potentially fatal reactions to sulfonamides Fatalities have occurred, although rarely, as a result of severe reactions to sulfonamides (eg, zonisamide), including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias. 

Zonisamide Blocks high-frequency firing via action on VG Na+ channels Approximately 70% bioavailable orally minimally bound to plasma proteins >50% metabolized ty2 50-70 h Generalized tonic-clonic seizures, partial seizures, myoclonic seizures Toxicity Drowsiness, cognitive impairment, confusion, poor concentration Interactions Minimal... 

Phenobarbital Phenytoin Primidone Felbamate Lamotrigine Tiagabide Topiramate Valproate Zonisamide Clobazam Clonazepam Diazepam usually compensated by the effect of the added drug risk of toxicity when interfering drug is discontinued drug... 

Ketoconazole Carbamazepine Zonisamide Risk of toxicity of the affected drugs Inhibition of metabolism of the affected drugs... 

Note Zonisamide is a sulfonamide and can he absorbed systemically. Sulfonamides can produce severe, possibly fatal, reactions such as toxic epidermal necrolysis and Stevens-Johnson syndrome... 

TOXICITY Zonisamide is well tolerated. Adverse effects include somnolence, ataxia, anorexia, nervousness, and fatigue. Approximately 1% of individuals develop renal calculi during treatment with zonisamide, probably related to its ability to inhibit carbonic anhydrase. 

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