zonisamide

Zonisamide is a sulfonamide antiepilepsy drug with sodium and calcium channel-blocking actions approved for the treatment of partial seizures.

During clinical trials evaluating its antiepileptic effect, it was noticed that patients on this medication had an associated weight loss; zonisamide is therefore sometimes used in clinical practice to induce weight loss.

The drug is partially metabolized by the P450 3A (CYP3A) enzyme; the patient’s genotype, CYP3A5*3/ *3 is present in 50% of whites and is unlikely to be responsible for this rare idiosyncratic adverse reaction.

Side effects

 drug-induced ductopenia (vanishing bile duct syndrome) (17122520)