Zonisamide

Zonisamide is a prescription medication used to treat partial seizures in adults. Zonisamide belongs to a group of drugs called anticonvulsants, which decrease abnormal electrical activity in the brain.

This medication comes in capsule form and is taken once or twice a day, with or without food.

Common side effects of zonisamide include drowsiness, loss of appetite, and dizziness.  Do not drive or operate machinery until you know how zonisamide affects you. 

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

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Zonisamide may be found in some form under the following brand names:

• Zonegran

Zonisamide can cause serious side effects including:

• The side effects mentioned (see "Drug Precautions").
• 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.

The most common side effects of zonisamide 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.

Tell your healthcare provider about any side effect that bothers you or that does not go away. These are not all of the possible side effects of zonisamide. For more information, ask your healthcare provider or pharmacist.

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

Tell your healthcare provider about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your healthcare provider if you take:

• medications that make you drowsy such as: sleep medicines, sedatives, tranquilizers, anti-anxiety drugs, narcotic pain relievers, psychiatric medicines, muscle relaxants, antihistamines, and others.
• carbamazepine (Carbatrol, Epitol, Equeto, Tegretol)
• carbonic anhydrase inhibitors such as acetazolamide (Diamox), dichlorphenamide (Daranide), methazolamide, topiramate (Topamax)
• phenobarbital (Luminal)
• phenytoin (Dilantin, Phenytek)
• primidone (Mysoline)

This is not a complete list of zonisamide drug interactions. Ask your healthcare provider or pharmacist for more information.

Zonisamide may cause serious side effects, including:

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

These serious side effects are described below.

1. Zonisamide may cause a serious skin rash that can cause death. These serious skin reactions are more likely to happen when you begin taking zonisamide within the first 4 months of treatment but may occur at later times.
2. 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:
   • a skin rash
   • high fever, recurring fever, or long lasting fever
   • less sweat than normal
3. 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 to 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).
4. 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.
5. Zonisamide may cause problems with your concentration, attention, memory, thinking, speech, or language.
6. 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 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.

• Do not take zonisamide if you are allergic to medicines that contain sulfa.
• Do not drink alcohol or take other drugs that make you sleepy or dizzy while taking zonisamide until you talk to your health care provider. Zonisamide 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.

Grapefruit and grapefruit juice may interact with zonisamide and lead to potentially dangerous effects. Discuss the use of grapefruit products with your healthcare provider.

Before taking zonisamide, 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

Tell your healthcare provider if you:

• are pregnant or plan to become pregnant. Zonisamide may harm your unborn baby. See "Pregnant" section.
• are breastfeeding or plan to breastfeed. 

Tell your healthcare provider about all the medicines you take including prescription and non-prescription medicines, vitamins or herbal supplements. Zonisamide and other medicines may affect each other causing side effects.

Know the medicines you take. Keep a list of them with you to show your healthcare provider and pharmacist each time you get a new medicine.

Tell your healthcare provider if you are pregnant or plan to become pregnant. Zonisamide 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.

• You and your healthcare provider should decide if you should take zonisamide 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.

Tell your healthcare provider if you 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.

• Take zonisamide exactly as prescribed. Your healthcare prescriber may change your dose. Your healthcare provider will tell you how much zonisamide to take.
• Take zonisamide 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 suddenly can cause serious problems, including seizures that will not stop (status epilepticus).

What you should avoid while taking zonisamide.

• Do not drink alcohol or take other drugs that make you sleepy or dizzy while taking zonisamide until you talk to your health care provider. Zonisamide 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.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

• other medical conditions you have
• other medications you are taking
• how you respond to this medication
• your kidney function

The recommended dose range of zonisamide for the treatment of partial seizures in adults is 100mg-400mg/day.

If you take too much zonisamide, call your local Poison Control Center or go to the nearest emergency room right away.

Active ingredient: zonisamide

Inactive ingredients: microcrystalline cellulose, hydrogenated vegetable oil, sodium lauryl sulfate, gelatin, and colorants.

• Store zonisamide between 59°F to 86°F (15°C to 30°C).
• Keep zonisamide dry and away from light.
• Keep zonisamide and all medicines out of the reach of children.