Zonisamide (Page 8 of 9)


The following serious adverse reactions have been reported since approval and use of zonisamide worldwide. These reactions are reported voluntarily from a population of uncertain size; therefore, it is not possible to estimate their frequency or establish a causal relationship to drug exposure.

Acute pancreatitis, rhabdomyolysis, increased creatine phosphokinase, drug reaction with eosinophilia and systemic symptoms (DRESS), acute myopia and secondary angle closure glaucoma, and hyperammonemia and encephalopathy (see WARNINGS).

To report SUSPECTED ADVERSE REACTIONS, contact Cipla Ltd. at 1-866-604-3268 or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.


The abuse and dependence potential of zonisamide has not been evaluated in human studies (see WARNINGS, Cognitive/Neuropsychiatric Adverse Events subsection). In a series of animal studies, zonisamide did not demonstrate abuse liability and dependence potential. Monkeys did not self-administer zonisamide in a standard reinforcing paradigm.

Rats exposed to zonisamide did not exhibit signs of physical dependence of the CNS-depressant type. Rats did not generalize the effects of diazepam to zonisamide in a standard discrimination paradigm after training, suggesting that zonisamide does not have abuse potential of the benzodiazepine-CNS depressant type.


Human Experience: Experience with zonisamide daily doses over 800 mg/day is limited. During zonisamide clinical development, three patients ingested unknown amounts of zonisamide as suicide attempts, and all three were hospitalized with CNS symptoms. One patient became comatose and developed bradycardia, hypotension, and respiratory depression; the zonisamide plasma level was 100.1 mcg/mL measured 31 hours post-ingestion. Zonisamide plasma levels fell with a half-life of 57 hours, and the patient became alert five days later.

Management: No specific antidotes for zonisamide overdosage are available. Following a suspected recent overdose, emesis should be induced or gastric lavage performed with the usual precautions to protect the airway. General supportive care is indicated, including frequent monitoring of vital signs and close observation.

Zonisamide has a long half-life (see CLINICAL PHARMACOLOGY section). Due to the low protein binding of zonisamide (40%), renal dialysis may be effective. The effectiveness of renal dialysis as a treatment of overdose has not been formally studied. A poison control center should be contacted for information on the management of zonisamide overdosage.


Zonisamide, USP is recommended as adjunctive therapy for the treatment of partial seizures in adults. Safety and efficacy in pediatric patients below the age of 16 have not been established. Zonisamide should be administered once or twice daily, using 25 mg or 100 mg capsules. Zonisamide is given orally and can be taken with or without food. Capsules should be swallowed whole.

Adults over Age 16: The prescriber should be aware that, because of the long half-life of zonisamide, up to two weeks may be required to achieve steady state levels upon reaching a stable dose or following dosage adjustment. Although the regimen described below is one that has been shown to be tolerated, the prescriber may wish to prolong the duration of treatment at the lower doses in order to fully assess the effects of zonisamide at steady state, noting that many of the side effects of zonisamide are more frequent at doses of 300 mg per day and above. Although there is some evidence of greater response at doses above 100 to 200 mg/day, the increase appears small and formal dose-response studies have not been conducted.

The initial dose of zonisamide should be 100 mg daily. After two weeks, the dose may be increased to 200 mg/day for at least two weeks. It can be increased to 300 mg/day and 400 mg/day, with the dose stable for at least two weeks to achieve steady state at each level. Evidence from controlled trials suggests that zonisamide doses of 100 to 600 mg/day are effective, but there is no suggestion of increasing response above 400 mg/day (see CLINICAL PHARMACOLOGY, Clinical Studies subsection). There is little experience with doses greater than 600 mg/day.

Patients with Renal or Hepatic Disease: Because zonisamide is metabolized in the liver and excreted by the kidneys, patients with renal or hepatic disease should be treated with caution, and might require slower titration and more frequent monitoring (see CLINICAL PHARMACOLOGY and PRECAUTIONS).


Zonisamide, USP is available as 100 mg two-piece hard gelatin capsules. The capsules imprinted with codes are printed in black ink. Zonisamide, USP is available in bottles with strengths and capsule description as follows:

Dosage Strength Capsule Description NDC#
100 mg 100 Count Size “1” Brown Opaque Cap and White Opaque Body imprinted with 100 mg on the cap and IG228 on the body in black ink, filled with White to Off-white powder. 69097-861-07
100 mg 500 Count Size “1” Brown Opaque Cap and White Opaque Body imprinted with 100 mg on the cap and IG228 on the body in black ink, filled with White to Off-white powder. 69097-861-12

Store at 20°C to 25°C (68°F to 77°F) [see USP Controlled Room Temperature], in a dry place and protected from light.

Revised: 07/2020

Medication Guide Zonisamide Capsules, USP(zoe nis’ a mide)

What is the most important information I should know about zonisamide capsules?

Zonisamide capsules may cause serious side effects, including:

  1. Serious skin rash that can cause death.
  2. Serious allergic reactions that may affect different parts of the body.
  3. Less sweating and increase in your body temperature (fever).
  4. Serious eye problems.
  5. Suicidal thoughts or actions in some people.
  6. Increased level of acid in your blood (metabolic acidosis).
  7. Problems with your concentration, attention, memory, thinking, speech, or language.
  8. Blood cell changes such as reduced red and white blood cell counts.

These serious side effects are described below.

1. Zonisamide capsules may cause a serious skin rash that can cause death. These serious skin reactions are more likely to happen when you begin taking zonisamide capsules within the first 4 months of treatment but may occur at later times.

2. Zonisamide can cause other types of allergic reactions or serious problems that may affect different parts of the body such as your liver, kidneys, heart, or blood cells. You may or may not have a rash with these types of reactions. These reactions can be very serious and can cause death. Call your health care provider right away if you have:

  • fever
  • severe muscle pain
  • rash
  • swollen lymph glands
  • swelling of your face
  • unusual bruising or bleeding
  • weakness, fatigue
  • yellowing of your skin or the white part of your eyes

3. Zonisamide may cause you to sweat less and to increase your body temperature (fever). You may need to be hospitalized for this. You should watch for decreased sweating and fever, especially when it is hot and especially in children taking Zonisamide.

Call your health care provider right away if you have:

  • high fever, recurring fever, or long lasting fever
  • less sweat than normal

4. Zonisamide may cause eye problems. Serious eye problems include:

  • sudden decrease in vision with or without eye pain and redness
  • a blockage of fluid in the eye causing increased pressure in the eye (secondary angle closure glaucoma)

These eye problems can lead to permanent loss of vision if not treated.

Call your healthcare provider right away if you have any new eye symptoms, including any eye pain or redness or any new problems with your vision.

5. Like other antiepileptic drugs, zonisamide may cause suicidal thoughts or actions in a very small number of people, about 1 in 500.

Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:

  • thoughts about suicide or dying
  • attempt to commit suicide
  • new or worse depression
  • new or worse anxiety
  • feeling agitated or restless
  • panic attacks
  • trouble sleeping (insomnia)
  • new or worse irritability
  • acting aggressive, being angry, or violent
  • acting on dangerous impulses
  • an extreme increase in activity and talking (mania)
  • other unusual changes in behavior or mood
  • Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes.

How can I watch for early symptoms of suicidal thoughts and actions?

  • Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings.
  • Keep all follow-up visits with your healthcare provider as scheduled.

Call your healthcare provider between visits as needed, especially if you are worried about symptoms.

Do not stop zonisamide without first talking to a healthcare provider.

Stopping zonisamide suddenly can cause serious problems. Stopping a seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus).

6. Zonisamide can increase the level of acid in your blood (metabolic acidosis). If left untreated, metabolic acidosis can cause brittle or soft bones (osteoporosis, osteomalacia, osteopenia), kidney stones and can slow the rate of growth in children. Metabolic acidosis can happen with or without symptoms.

Sometimes people with metabolic acidosis will:

  • feel tired
  • not feel hungry (loss of appetite)
  • feel changes in heartbeat
  • have trouble thinking clearly

Your healthcare provider should do a blood test to measure the level of acid in your blood before and during your treatment with zonisamide.

7. Zonisamide may cause problems with your concentration, attention, memory, thinking, speech, or language.

8. Zonisamide can cause blood cell changes such as reduced red and white blood cell counts. call your healthcare provider if you develop fever, sore throat, sores in your mouth or unusual bruising.

Zonisamide capsules can have other serious side effects. For more information ask your healthcare provider or pharmacist. Tell your healthcare provider if you have any side effect that bothers you. Be sure to read the section titled “What are the possible side effects of zonisamide capsules?”

What is zonisamide?

Zonisamide is a prescription medicine that is used with other medicines to treat partial seizures in adults.

It is not known if zonisamide is safe or effective in children under 16 years of age.

Do not take zonisamide capsules:

Do not take zonisamide capsules if you are allergic to medicines that contain sulfa.

Before taking zonisamide capsules, tell your healthcare provider about all your medical conditions, including if you:

  • have or have had depression, mood problems or suicidal thoughts or behavior
  • have kidney problems
  • have liver problems
  • have a history of metabolic acidosis (too much acid in your blood)
  • have weak, brittle bones or soft bones (osteomalacia, osteopenia or osteoporosis)
  • have a growth problem
  • are on a diet high in fat called a ketogenic diet
  • have diarrhea
  • have high blood levels of ammonia

Tell your healthcare provider if you:

  • are pregnant or plan to become pregnant. Zonisamide capsules may harm your unborn baby. Women who can become pregnant should use effective birth control. Tell your healthcare provider right away if you become pregnant while taking zonisamide capsules.
    You and your healthcare provider should decide if you should take zonisamide capsules while you are pregnant.
    If you become pregnant while taking zonisamide, talk to your healthcare provider about registering with the North American Antiepileptic Drug Pregnancy Registry. You can enroll in this registry by calling 1-888-233-2334. The purpose of this registry is to collect information about the safety of antiepileptic drugs during pregnancy.
  • are breastfeeding or plan to breastfeed. Zonisamide can pass into your breast milk. It is not known if zonisamide in your breast milk can harm your baby. Talk to your healthcare provider about the best way to feed your baby if you take zonisamide capsules.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins or herbal supplements.

How should I take zonisamide capsules?

  • Take zonisamide capsules exactly as prescribed. Your healthcare prescriber may change your dose. Your healthcare provider will tell you how much zonisamide to take.
  • Take zonisamide capsules with or without food.
  • Swallow the capsules whole.
  • If you take too much zonisamide, call your local Poison Control Center or go to the nearest emergency room right away.
  • Do not stop taking zonisamide without talking to your healthcare provider. Stopping zonisamide capsules suddenly can cause serious problems, including seizures that will not stop (status epilepticus).

What should I avoid while taking zonisamide capsules?

  • Do not drink alcohol or take other drugs that make you sleepy or dizzy while taking zonisamide capsules until you talk to your health care provider. Zonisamide capsules taken with alcohol or drugs that cause sleepiness or dizziness may make your sleepiness or dizziness worse.
  • Do not drive, operate heavy machinery, or do other dangerous activities until you know how zonisamide affects you. Zonisamide can slow your thinking and motor skills.

What are the possible side effects of zonisamide capsules?

Zonisamide capsules can cause serious side effects. See “What is the most important information I should know about zonisamide capsules ?”

Other serious side effects include:

  • kidney stones: Back pain, stomach pain, or blood in your urine may mean you have kidney stones. Drink plenty of fluids while you take zonisamide to lower your chance of getting kidney stones.
  • problems with mood or thinking (new or worse depression; sudden changes in mood, behavior, or loss of contact with reality, sometimes associated with hearing voices or seeing things that are not really there; feeling sleepy or tired; trouble concentrating; speech and language problems). Call your healthcare provider right away if you have any of the symptoms listed above.
  • high blood ammonia levels. High ammonia in the blood can affect your mental activities, slow your alertness, make you feel tired, or cause vomiting.

The most common side effects of zonisamide capsules include:

  • drowsiness
  • loss of appetite
  • dizziness
  • problems with concentration or memory
  • trouble with walking and coordination
  • agitation or irritability

Side effects can happen at any time, but are more likely to happen during the first several weeks after starting zonisamide capsules.

These are not all of the possible side effects of zonisamide capsules.

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

How should I store zonisamide capsules?

  • Store zonisamide capsules at 20°C to 25°C (68°F to 77°F) [see USP Controlled Room Temperature]
  • Keep zonisamide capsules dry and away from light

Keep zonisamide capsules and all medicines out of the reach of children.

General Information about the safe and effective use of zonisamide capsules

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use zonisamide for a condition for which it was not prescribed. Do not give zonisamide capsules to other people, even if they have the same symptoms that you have. It may harm them. You can ask your pharmacist or healthcare provider for information about zonisamide capsules that is written for health professionals.

For more information, call Cipla Ltd. at 1-866-604-3268.

What are the ingredients in zonisamide capsules?

Active ingredient: zonisamide USP

Inactive ingredients: microcrystalline cellulose, hydrogenated vegetable oil, gelatin and colorants. Components of gelatin capsules (For 100 mg: titanium dioxide, gelatin and FDA/E172 red iron oxide). Imprint ink dye (Black SW- 9008/SW-9009)

This Medication Guide has been approved by the U.S. Food and Drug Administration.

Manufactured by:
InvaGen Pharmaceuticals, Inc.
(a subsidiary of Cipla Ltd.)
Hauppauge, NY 11788

Manufactured for:
Cipla USA, Inc.
10 Independence Boulevard, Suite 300 Warren, NJ 07059

Revised: 07/2020

Barcode: 861-07-2020

SAP Code: 21081985

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