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Generic Name:

zonisamide, Oral capsule

All Brands

  • Zonegran
SECTION 1 of 5

Highlights for zonisamide

Oral capsule
1

Zonisamide is an oral drug that’s used to treat and prevent partial seizures caused by epilepsy.

2

This drug is used with other medications to help control and prevent future seizures.

3

The standard starting dose is 100 mg taken by mouth once per day. Your doctor may increase your dose from there depending on how you tolerate and respond to this drug.

4

Common side effects include drowsiness, loss of appetite, dizziness, problem with concentration or memory, trouble with walking and coordination, and agitation or irritability.

5

You shouldn’t stop taking zonisamide suddenly. This can lead to serious side effects, such as seizures that don’t stop (status epilepticus).

IMPORTANT INFORMATION

Metabolic acidosis warning

This drug can increase the level of acid in your blood, causing metabolic acidosis. This condition can be serious. You may be more likely to develop metabolic acidosis if you have:

  • kidney disease
  • lung disease
  • episodes of seizures that don’t stop (status epilepticus)
  • a high fat diet (ketogenic diet)
  • diarrhea

Tell your doctor if you have symptoms of this condition, such as:

  • tiredness
  • loss of appetite
  • changes to your heart rhythm  
  • trouble thinking clearly
  • rapid breathing (hyperventilation)

Suicidal thoughts

This drug can increase your risk of suicidal thoughts or behavior. Your doctor will watch you for signs of worsening depression, suicidal thoughts or behavior, or any unusual changes in mood or behavior.

High body temperature

This drug can cause your body temperature to increase and cause you to sweat less. This can lead to hospitalization. Children and people who are taking the drugs topiramate or acetazolamide have a higher risk. Your risk is also increased in warm or hot weather. Tell your doctor right away if you have:

  • a fever
  • a fever that doesn’t go away or keeps coming back
  • less sweating
  • a skin rash

Serious skin reactions

This drug may cause serious skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis. These may be life threatening. This reaction is most likely to happen within the first 16 weeks of treatment with this drug, but it may occur at any time. Symptoms can include:

  • skin rash
  • raw areas of skin
  • sores in your mouth, nose, or around your eyes
  • peeling or blistering skin

What is zonisamide?

This drug is a prescription drug. It’s available as an oral capsule.

This drug is available as a generic drug. Generic drugs usually cost less. In some cases they may not be available in every strength or form as the brand. Talk to your healthcare provider to see if the generic will work for you.

This drug may be used as part of a combination therapy with other medications that treat seizures. That means you need to take it with other drugs.

Why it's used

This drug is used as an add-on treatment for partial seizures in adults and children 16 years of age and older with epilepsy.

How it works

This drug belongs to a class of drugs called anticonvulsants. A class of drugs refers to medications that work similarly.

More Details

How it works

This drug belongs to a class of drugs called anticonvulsants. A class of drugs refers to medications that work similarly. They have a similar chemical structure and are often used to treat similar conditions.

This drug works by blocking sodium and calcium channels found on nerve cells in your brain. This stops electrical signals from building up and spreading across the brain, which is what happens during a seizure. This prevents and stops the spread of seizures.

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SECTION 2 of 5

zonisamide Side Effects

Oral capsule

Most Common Side Effects

The most common side effects that occur with zonisamide include:

  • drowsiness

  • loss of appetite

  • dizziness

  • problems with concentration or memory

  • trouble with walking or coordination

  • agitation or irritability

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 9-1-1.

  • serious skin rash. This rash can be fatal. Symptoms include:

    • skin rash
    • raw areas of skin
    • sores in your mouth, nose, or around your eyes
    • peeling or blistering skin
  • less sweating and an increase in body temperature (fever)

  • thoughts or behaviors of hurting yourself. Symptoms include:

    • thoughts about suicide or dying
    • attempts to commit suicide
    • new or worse depression or anxiety
    • feeling agitated or restless
    • panic attacks
    • trouble sleeping
    • new or worse irritability
    • acting aggressive, angry, or violent
    • acting on dangerous impulses
    • extreme increases in activity and talking
    • other unusual change in mood or behavior
  • increased level of acid in your blood (metabolic acidosis). Symptoms include:

    • tiredness
    • loss of appetite
    • changes to your heart rate
    • trouble thinking clearly
    • rapid breathing (hyperventilation)
  • cognitive side effects. Symptoms include:

    • problems with your coordination
    • trouble paying attention or concentrating
    • memory problems
    • slowed thinking
    • trouble speaking or finding the right word
  • blood cell changes, such as reduced white or red blood cell counts. Symptoms include:

    • frequent infections
    • an infection that won’t go away
    • fatigue
    • unexplained or easy bruising
    • frequent nosebleeds
  • kidney stones. Symptoms include:

    • pain with urination
    • severe pain in your side or back
    • increased frequency of urination
    • urinating small amounts of urine
    • pink, red, or brown urine
    • nausea
    • vomiting
  • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). This is an allergic reaction that can affect all organs. This can be life-threatening. Symptoms can include:

    • fever
    • rash
    • swelling of your face
    • lymph node disease
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

This drug can make you feel sleepy, dizzy, or slow your thinking and motor skills. You shouldn’t drive, use machinery, or do similar tasks that require alertness until you know how this drug affects you.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 5

zonisamide May Interact with Other Medications

Oral capsule

Zonisamide can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Alcohol interaction

You shouldn’t drink alcohol while taking zonisamide. Alcohol can make you feel even more sleepy or dizzy.

Medications that might interact with this drug

Glaucoma drugs

Certain glaucoma drugs can increase the amount of acid in your body. Taking these drugs with zonisamide can increase your risk for metabolic acidosis and also kidney stones.

These drugs include:

  • acetazolamide

Herbal supplement
  • St. John’s wort

This herbal supplement can increase the body’s breakdown of zonisamide. This can lead to lower levels in your blood, which means the drug may not work as well to control your seizures.

Periodic paralysis drugs

Certain periodic paralysis drugs can increase the amount of acid in your body. Taking these drugs with zonisamide can increase your risk for metabolic acidosis and also kidney stones.

These drugs include:

  • dichlorphenamide

Seizure drugs

Certain seizure drugs can increase the body’s breakdown of zonisamide. This can lead to lower levels in your blood, which means the drug may not work as well to control your seizures.

These drugs include:

  • phenytoin
  • carbamazepine
  • phenobarbital
  • divalproex

Seizure and migraine medicines

Certain drugs used for both seizures and migraines can increase the amount of acid in your body. Taking these drugs with zonisamide can increase your risk for metabolic acidosis and also kidney stones.

These drugs include:

  • topiramate

Tuberculosis drugs

Certain tuberculosis drugs can increase the body’s breakdown of zonisamide. This can lead to lower levels in your blood, which means the drug may not work as well to control your seizures.

These drugs include: 

  • rifampin
  • rifabutin
  • rifapentine

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Drug warnings
sulfa allergies
People with sulfa allergies

You shouldn’t take this drug if you’re allergic to medicines that contain sulfa. You may also have an allergic reaction to this drug.

kidney disease
People with kidney disease

This drug is cleared from your body by your kidneys. If you have kidney damage or kidney disease, this drug could build up in your blood and cause more side effects and toxicity. Your doctor may adjust your dose of this drug.

liver disease
People with liver disease

This drug is broken down by your liver. If you have liver damage or liver disease, this drug could build up in your blood and cause more side effects and toxicity. Your doctor may adjust your dose of this drug.

Pregnant women
Pregnant women

This drug is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Tell your doctor if you’re pregnant or plan to become pregnant. This drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Women who are breast-feeding
Women who are breast-feeding

This drug passes into breast milk and can cause serious effects in a breastfeeding child.

You and your doctor may need to decide if you’ll take this drug or breastfeed.

For seniors
For seniors

Older adults may process drugs more slowly. A normal adult dose may cause levels of the drug to be higher than normal in your body. You may need a lower dose of this drug or you may need a different schedule.

For children
For children

This medicine hasn’t been studied in children and shouldn’t be used in children under the age of 16 years.

When to call the doctor
When to call the doctor

Call your doctor if you start having more seizures or a different type of seizure.

allergies
Allergies

This drug can cause a severe allergic reaction. Symptoms include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives
  • rash

Don’t take this drug again if you’ve ever had an allergic reaction to it or sulfa drugs. Taking it again could be fatal (cause death).

SECTION 4 of 5

How to Take zonisamide (Dosage)

Oral capsule

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Add-on treatment for partial seizures in epilepsy

Brand: Zonegran

Form: Oral capsule
Strengths: 25 mg, 100 mg

Generic: zonisamide

Form: Oral capsule
Strengths: 25 mg, 50 mg, 100 mg
Adult dosage (ages 18–64 years)
  • The standard starting dose is 100 mg taken by mouth once per day.
  • After two weeks, your doctor may increase your dose to 200 mg per day.
  • Your doctor may continue to increase your daily dose by 100 mg every 2 weeks to a maximum recommended dose of 400 mg per day.
Child dosage (ages 16–17 years)
  • The standard starting dose is 100 mg taken by mouth once per day.
  • After two weeks, your doctor may increase your dose to 200 mg per day.
  • Your doctor may continue to increase your daily dose by 100 mg every 2 weeks to a maximum recommended dose of 400 mg per day.
Child dosage (ages 0–15 years)

This medicine hasn’t been studied in children and shouldn’t be used in children under the age of 16 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of the drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dose or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Special considerations

Kidney Disease: If you have kidney damage or kidney disease, your doctor may lower your dose of zonisamide. Your doctor may increase your dose more slowly and monitor you more closely.

Liver Disease: If you have liver damage or liver disease, your doctor may lower your dose of zonisamide. Your doctor may increase your dose more slowly and monitor you more closely.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

This drug comes with serious risks if you don’t take it as prescribed.

If you don’t take It at all

If you don’t take this drug at all, your seizures won’t get better.

If you stop taking it suddenly

You shouldn’t stop taking this drug without taking to your doctor. Stopping this drug suddenly can cause serious problems, such as seizures that won’t stop (status epilepticus).

If you take too much

If you take too much of this drug, you might have the following symptoms:

  • slowed heart rate
  • slowed breathing
  • low blood pressure
  • lightheadedness
  • loss of consciousness

If you take too much this drug, call your local poison control center or go to the emergency room right away.

What to do if you miss a dose

Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working

You’ll know that this drug is working if your seizures stop or become less frequent.

This drug is used for long-term treatment.

Important considerations for taking this drug

Store this drug from 59–86°F (15–30°C)

Don’t freeze this drug.

Keep it away from light and high temperature.

Keep your drugs away from areas where they could get wet, such as bathrooms. Store this drug away from moisture and damp locations.

Travel

When traveling with your medication:

  • Always carry your medication with you, such as in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

Before starting and regularly during treatment with this drug, your doctor may check the following:

  • blood cell counts
  • kidney function
  • liver function
  • cognitive function
  • blood pH
  • bicarbonate levels
  • temperature

Your doctor may also monitor you for the following:

  • seizures. You and your doctor should monitor how often you have seizures.
  • mental health and behavioral problems. This drug can cause new or worsen existing mental health and behavioral problems. You and your doctor should watch for any unusual changes in your behavior and mood.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

SECTION 5 of 5

How Much Does zonisamide Cost?

Oral capsule

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Lowest price for zonisamide

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Kroger Pharmacy $17.54
These prices represent the lowest priced national pharmacies for zonisamide on GoodRx. They may be lower than your insurance.

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These prices represent the lowest priced national pharmacies for zonisamide on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on May 20, 2016

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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