Zonisamide (ZNS)

Zonisamide is a sulfonamide anticonvulsant approved for use as an adjunctive therapy in adults with partial-onset seizures; infantile spasm, mixed seizure types of Lennox-Gastaut syndrome, myoclonic, and generalized tonic clonic seizure. Zonisamide and other carbonic anhydrase inhibitors such as topiramate, furosemide, and hydrochlorothiazide have been known to interfere with amobarbital, which has led to inadequate anesthetization during the Wada test. Zonisamide may also interact with other carbonic anhydrase inhibitors to increase the potential for metabolic acidosis. Additionally, the metabolism of zonisamide is inhibited by ketoconazole, ciclosporin, miconazole, fluconazole and carbamazepine (in descending order of inhibition) due to their effects on the CYP3A4 enzyme. Zonisamide is an antiseizure drug chemically classified as a sulfonamide and unrelated to other antiseizure agents.