Zonisamide (Zonegran): Basics, Side Effects & Reviews
Zonisamide (Zonegran)

Zonisamide (Zonegran)

Basics, Side Effects, Reviews & More

Zonisamide (Zonegran) is used with other medications to help control partial seizures. It can't be used by itself.






Not a controlled medication


Lower-cost generic available


Prescription only

Reviewed by:

Ly Neal, PharmD

Alyssa Billingsley, PharmD

Sarah Gupta, MD

Last reviewed on:

October 30, 2020


What is zonisamide (Zonegran)?

How zonisamide (Zonegran) works

Zonisamide (Zonegran) is a sulfonamide. It's not exactly clear how it controls seizures, but it may stop nerves from sending signals that can cause seizures.

What is zonisamide (Zonegran) used for?

  • Partial seizure

Zonisamide (Zonegran) dosage forms

Typical dosing for zonisamide (Zonegran)

The typical starting dose of zonisamide (Zonegran) is 100 mg by mouth daily (taken all at once or divided into two doses). Your provider may increase the dose after two weeks based on your response to the medication. The typical dosing range is from 100 mg to 600 mg by mouth daily.

Frequently asked questions about zonisamide (Zonegran)

Pros and cons of zonisamide (Zonegran)


Thumbs UpAvailable as a lower cost generic

Thumbs UpCan be given once a day, so it's easier to remember

Thumbs UpYou can take zonisamide (Zonegran) with or without food

Thumbs UpCan be a good add-on to control your seizures when other antiseizure medications are not as effective on their own


Thumbs DownOnly used with other medications to help control your seizures

Thumbs DownOnly approved in people age 16 or older

Thumbs DownYou can't take this medication if you have a sulfa allergy

Thumbs DownShould only be used in pregnancy if the benefit outweighs the potential risk to the unborn baby

Pharmacist tips for zonisamide (Zonegran)

Capsule IconYou're more likely to get overheated while taking zonisamide (Zonegran). Make sure you drink plenty of liquids, don't exercise too hard, and don't stay out in the sun if it's hot out. If you notice decreased sweating or high, recurring, or long lasting fever, contact your provider right away because this can be a sign of something more serious.

Capsule IconThis medication may increase your risk for kidney stones. Drinking extra fluids will make you urinate more which will help prevent kidney problems.

Capsule IconDon't stop taking zonisamide (Zonegran) suddenly without talking to your provider, as your seizures can get worse.

Capsule IconBe very careful drinking alcohol or taking medications for pain or anxiety while taking zonisamide (Zonegran) because your breathing can become dangerously slow.

Capsule IconZonisamide (Zonegran) can increase the level of acid in your blood (called metabolic acidosis). Your provider may want to monitor your blood work before starting and while you are taking this medication. Let your provider know if you begin to feel more tired, lose your appetite, notice a change in your heartbeat, or have trouble thinking clearly.

Prices for zonisamide (Zonegran) start at just $15.84 with a GoodRx coupon. They’re fast, easy-to-use and free!

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What are the side effects of zonisamide (Zonegran)?

With any medication, there are risks and benefits. Even if the medication is working, you may experience some unwanted side effects.

Warning Small Contact your doctor immediately if you experience any of the following:

  • Serious skin reactions or severe rash
  • Signs of an allergic reaction (swelling of the face and neck area, trouble breathing, rash)
  • Signs of sudden liver problems (abdominal pain, tremors, confusion, yellowing of skin or eyes)
  • Signs of serious blood disorders (fever, sore throat, sores in your mouth, unusual bruising)
  • Sweating less than usual (with or without fever), especially when in the heat
  • Worsening depression, unusual changes in mood or behavior, suicidal thoughts
  • Blurred vision, eye pain, or other vision changes
  • Sudden back pain, abdominal pain, or blood in the urine
  • Fast breathing, unusual tiredness, loss of appetite, fast or irregular heartbeat

Caution Small The following side effects may get better over time as your body gets used to the medication. Let your doctor know immediately if you continue to experience these symptoms or if they worsen over time.

Common side effects

  • Sleepiness (17%)
  • Dizziness (13%)
  • Loss of appetite (13%)
  • Headache (10%)
  • Nausea (9%)
  • Agitation/irritability (9%)
  • Fatigue (8%)
  • Tiredness (7%)
  • Depression (6%)
  • Problems with concentration or memory (6%)
  • Stomach pain (6%)
  • Double vision (6%)

Other side effects

  • Diarrhea (5%)
  • Speech problems (5%)
  • Flu-like symptoms (4%)
  • Tingling in your arms, hands, or feet (4%)
  • Indigestion (3%)
  • Weight loss (3%)
  • Anxiety (3%)
  • Rash (3%)
  • Constipation (2%)
  • Dry mouth (2%)
  • Impaired sense of taste (2%)

Source: FDA

The following side effects have also been reported:

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common


double vision

feeling sad or empty


lack of appetite

loss of interest or pleasure

mood or mental changes

shakiness or unsteady walking


trouble with concentrating

trouble with sleeping

Less common





large, flat blue or purplish patches on the skin


Incidence not known

Blurred vision

change in near or distance vision

difficulty in focusing eyes

eye pain

increase in frequency of seizures

swelling of the face

yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Abdominal or stomach pain



difficulty with memory


double vision


loss of appetite




unusual drowsiness

unusual tiredness or weakness

Less common

Aching muscles or joints

acid or sour stomach

bad, unusual, or unpleasant taste in the mouth


change in taste



difficulty with speaking

difficulty with thinking

dry mouth


general ill feeling




mental slowness


runny or stuffy nose


tingling, burning, or prickly feelings on the skin

uncontrolled, back and forth, or rolling eye movements

weight loss

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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

What are the risks and warnings for zonisamide (Zonegran)?

Zonisamide (Zonegran) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options

Sulfa medication allergy

  • Risk factors: Allergy to sulfonamides such as Septra or Bactrim

Don’t take zonisamide (Zonegran) if you're allergic to sulfa medications since you might have a severe allergic reaction. Seek medical attention immediately or go the emergency room if you notice a skin rash, swelling of the face or throat, or have difficulty breathing.

Lower blood cell counts

Zonisamide (Zonegran) can cause dangerous drops in blood cell counts. This can make you more likely to get sick or bleed. Talk to your provider if you get fevers more often or bleed or bruise easily. Regular blood tests can be done to ensure that your blood cell counts are within normal range.

Heat stroke and less sweating

  • Risk factors: Under age 18

Zonisamide (Zonegran) makes it harder to control your body temperature because you're less likely to sweat. It might make you more likely to have a heat stroke. Drink plenty of liquids, stay in the shade, and don't stay out in the sun too long if the weather is hot.

Suicidal behavior

  • Risk factors: Taking other medications to control seizures

Zonisamide (Zonegran), like other medications used to control seizures, can raise the risk of suicidal thoughts. If your mood worsens and you want to hurt yourself after you start taking zonisamide (Zonegran), talk to your provider right away.

Higher blood acid

  • Risk factors: Diarrhea | Kidney disease | Severe COPD or lung disease

Rarely, zonisamide (Zonegran) can raise the level of acid in your blood (metabolic acidosis). If not treated in time, it can cause kidney stones, or weaken your bones and make them likely to fracture. Metabolic acidosis can also lead to increased levels of ammonia in the blood which may affect the brain and cause you to become more tired, unable to concentrate, or vomit. Your provider might do regular blood tests to make sure you're healthy.

Withdrawal seizures

Talk to your provider before stopping zonisamide (Zonegran). Stopping zonisamide (Zonegran) suddenly can cause your seizures to come back, or become worse. Your provider will work with you to lower your dose slowly so this doesn't happen.

Serious skin reactions

Although rare, zonisamide (Zonegran) can cause fatal skin reactions. In most cases, people start out with flu-like symptoms (such as fever, cough, sore throat, and fatigue) that develop into painful rashes and blisters on the body. Let your provider know if you notice any unusual rashes while on zonisamide (Zonegran).

Serious allergic reactions involving organs

Zonisamide (Zonegran) can cause serious allergic reactions involving certain organs (such as heart, kidneys, and liver). Symptoms of such allergic reactions include fever, rash, severe muscle pain, swelling of the face, and yellowing of the skin or white part of the eyes. Let your provider know right away or seek immediate medical attention if you notice any of these symptoms while on zonisamide (Zonegran).

Serious eye problems

Zonisamide (Zonegran) can cause increased pressure in the eyes that can lead to blurred vision, eye pain, and eye redness. If left untreated, it can also lead to permanent loss of vision. Let your provider know if you start having eye problems while on zonisamide (Zonegran).

Problems with mood or thinking

Zonisamide (Zonegran) can make it harder for you to concentrate or remember things. It can also cause problems with speech, coordination, mood (new or worsening depression), and make you more sleepy. Be careful driving or doing anything that requires mental alertness while on zonisamide (Zonegran).

Serious birth defects

  • Risk factors: Women of child bearing age

Zonisamide (Zonegran) can have serious risks to the unborn baby such as heart defects or even death. Your provider might recommend you to take a form of birth control while on zonisamide (Zonegran) if you're a woman of child bearing age. Since this medication can cause serious birth defects, zonisamide (Zonegran) should only be used in pregnancy if the potential benefit outweighs the risk to the unborn baby.

Interactions between zonisamide (Zonegran) and other medications

Zonisamide (Zonegran) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with zonisamide (Zonegran). Please note that only the generic name of each medication is listed below.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Methenamine

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Aminolevulinic Acid
  • Ginkgo

How much does zonisamide (Zonegran) cost?

Zonisamide (Zonegran) is available as a generic medication and may be significantly cheaper compared to the brand version. Unless there is a specific reason you need the brand, the generic medication will be a better value. For even more savings, use a GoodRx coupon and pay just a fraction of the retail price.

Lowest GoodRx Price
Zonegran (brand)


Lowest GoodRx Price
zonisamide (generic)


View Prices & Coupons

Pricing based on most commonly-filled versions: 120 capsules of zonisamide 100mg

What are alternatives to zonisamide (Zonegran)?

There are a number of medications that your doctor can prescribe in place of zonisamide (Zonegran). Compare a few possible alternatives below.

Zonisamide (Zonegran)
Drug Class:Antiepileptic


lowest GoodRx price

View Prices
Pregabalin (Lyrica)
Drug Class:Antiepileptic


lowest GoodRx price

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