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Zonisamide (By mouth)

Zonisamide (zoe-NIS-a-mide)

Treats partial seizures.

Brand Name(s):


There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to zonisamide or other sulfa drugs.

How to Use This Medicine:

Capsule, Tablet

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
  • Swallow the capsule whole. Do not break, chew, or open it.
  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some medicines can affect how zonisamide works. Tell your doctor if you are using acetazolamide, dichlorphenamide, or topiramate.
  • Tell your doctor if you are on a ketogenic diet (high-fat, low-carbohydrate diet).
  • Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol.

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, breathing or lung problems, osteoporosis, or a history of metabolic acidosis.
  • This medicine may cause depression or thoughts of suicide. Tell your doctor if you have a history of depression or mental health problems.
  • This medicine may cause the following problems:
    • Serious skin reactions
    • Drug reaction with eosinophilia and systemic symptoms (DRESS), which may damage organs such as the liver, kidney, or heart
    • Metabolic acidosis (too much acid in your blood), which can lead to kidney stones and slow growth in children
  • This medicine may make you sweat less and cause your body temperature to increase. Use caution when you exercise or if you are outside in hot weather.
  • Drink extra fluids so you will urinate more often and help prevent kidney problems.
  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely. Your seizures may increase if you stop taking this medicine suddenly.
  • This medicine may make you drowsy or dizzy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, red skin rash
  • Decreased sweating
  • Depression, unusual changes in moods or behavior, thoughts of hurting yourself or others
  • Fast breathing, loss of appetite, unusual tiredness, fast, pounding, or uneven heartbeat
  • Fever, sore throat, sores or ulcers in the mouth or on the lips, easy bruising
  • Painful or difficult urination, bloody urine, decrease in how much you urinate, sudden and severe back or stomach pain
  • Problems with speech, coordination, concentration, or memory
  • Swollen, painful, or tender lymph glands in neck, armpit, or groin

If you notice these less serious side effects, talk with your doctor:

  • Sleepiness, drowsiness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 5/1/2020

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