The only people who definitely should not take zonisamide are those who are allergic to it or to other medicines in the same family, called sulfonamides. If you have ever been told that you're allergic to sulfa drugs (such as Bactrim or Septra), you should not take zonisamide, or take it only after carefully discussing it with your doctor.

Because zonisamide is metabolized in the liver and eliminated in the urine, people with liver and kidney disease should be treated with caution. The dosage may have to be increased more slowly.