The precise mechanism of action is unknown although it is believed that the drug prevents seizures by blocking both sodium and calcium channels and reduces voltage-dependent transient inward currents, consequently stabilizing neuronal membranes and suppressing neuronal hypersynchronization. Zonisamide is a sulfonamide and should not be taken by people allergic to sulfonamides. It is recommended that patients drink at least 6 to 8 glasses of water daily to prevent kidney stones. Common adverse effects include drowsiness, dizziness, nausea, anorexia, headache, and agitation. This drug may have some deleterious psychiatric effects including depression.
Psychological effects are much less common however.
The drug should be used with caution in patients with reduced kidney function. Despite all of the potentially negative aspects of the drug, it is an important option for epilepsy patients.