Zonisamide (By mouth)


Zonisamide (zoe-NIS-a-mide)

Treats partial seizures in adults with epilepsy. May be used together with other anti-seizure medicines. Belongs to a class of drugs called sulfonamides (sulfa drugs).

Brand Name(s)


When This Medicine Should Not Be Used

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.
  • Drink extra fluids so you will urinate more often and help prevent kidney problems.
  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.

If a dose is missed:

  • 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.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid

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

  • Make sure your doctor knows if you are also using acetazolamide (Diamox®), atropine, dichlorphenamide (Daranide®), dicyclomine (Bentyl®), dorzolamide (Trusopt®), glycopyrrolate (Robinul®), hyoscyamine (Cystospaz®), propantheline (Pro-Banthine®), scopolamine (Transderm Scop®), topiramate (Topamax®), or other seizure medicines (such as carbamazepine, phenobarbital, phenytoin, valproate, Dilantin®, or Tegretol®).
  • Tell your doctor if you are on a ketogenic diet (high-fat, adequate-protein, low-carbohydrate diet).
  • Do not drink alcohol while you are using this medicine.
  • Tell your doctor if you drink alcohol or if you are using any medicine that makes you sleepy, such as allergy medicine or narcotic pain medicine.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or breastfeeding. Tell your doctor if you have kidney disease, liver disease, bone problems (such as osteoporosis), breathing or lung problems, a history of metabolic acidosis, or a history of mood problems or depression.
  • This medicine may cause rare side effects that can be very serious. Call your doctor right away if you develop a skin rash, fever, sore throat, sores in your mouth, or easy bruising.
  • Serious skin reactions can occur with this medicine. Check with your doctor right away if you have blistering, peeling, or loosening of the skin, red skin lesions, severe acne or skin rash, sores or ulcers on the skin, or fever or chills.
  • This medicine may make you sweat less, which causes your body temperature to increase. Use extra care not to become overheated during exercise or hot weather.
  • This medicine may cause some people to have suicidal thoughts and tendencies or to become more depressed. If you notice these side effects or any unusual changes in behavior or mood, tell your doctor right away.
  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely. Stopping this medicine all at once could cause you to have seizures.
  • This medicine may make you dizzy or drowsy. Do not drive, use machines, or do anything else that could be dangerous until you know how this medicine affects you.
  • Check with your doctor right away if you have sudden back pain, stomach pain, or bloody or dark urine. These may be symptoms of kidney stones.
  • Call your doctor right away if you have fast breathing, loss of appetite, unusual tiredness or weakness, or a fast, pounding, or uneven heartbeat. These may be symptoms of metabolic acidosis.
  • This medicine may affect your child's growth. Your doctor may need to check your child's height and weight during treatment with this medicine.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

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
  • Black, tarry stools
  • Blistering, peeling, red skin rash
  • Changes in behavior, or thoughts of hurting yourself or others
  • Decreased sweating
  • Fast breathing, loss of appetite, unusual tiredness or weakness, or a fast, pounding, or uneven heartbeat
  • Feeling agitated, depressed, nervous, or irritable
  • Fever, chills, cough, sore throat, and body aches
  • Painful or difficult urination, blood in your urine, or decrease in the amount of urine
  • Sores or ulcers in the mouth or on the lips
  • Sudden and severe back or stomach pain
  • Unusual bleeding or bruising
  • Worsening of seizures

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

  • Dizziness, drowsiness, or lack of coordination
  • Problems with speech, balance, or walking
  • Trouble concentrating or remembering things

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

Version Info

  • Last reviewed on 8/4/2014

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