Zonisamide

WHY is this medicine prescribed?

Zonisamide is used in combination with other medications to treat certain types of seizures. Zonisamide is in a class of medications called anticonvulsants. It works by decreasing abnormal electrical activity in the brain.

HOW should this medicine be used?

Zonisamide comes as a capsule to take by mouth. It is usually taken once or twice a day with or without food. To help you remember to take zonisamide, take it at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take zonisamide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the capsules whole; do not split, chew, or crush them.

Your doctor will probably start you on a low dose of zonisamide and gradually increase your dose, not more often than once every 2 weeks.

Zonisamide may help control your condition but will not cure it. It may take 2 weeks or longer before you feel the full benefit of zonisamide. Continue to take zonisamide even if you feel well. Do not stop taking zonisamide without talking to your doctor, even if you experience side effects such as unusual changes in behavior or mood. If you suddenly stop taking zonisamide, your seizures may become worse. Your doctor will probably decrease your dose gradually.

Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with zonisamide and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (https://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer's website to obtain the Medication Guide.

Are there OTHER USES for this medicine?

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

What SPECIAL PRECAUTIONS should I follow?

Before taking zonisamide,

• tell your doctor and pharmacist if you are allergic to zonisamide, diuretics ('water pills'), oral medications for diabetes, sulfa drugs, or any other medications.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take while taking zonisamide. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• the following herbal product may interact with zonisamide: St. John's wort. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking zonisamide. Do not start any of these medications while taking zonisamide without discussing with your healthcare provider..
• tell your doctor if you are following a ketogenic diet (a high fat, low carbohydrate diet used to control seizures) or if you have or have ever had breathing problems, kidney liver, or lung disease. Also tell your doctor if you have diarrhea now, or if you develop diarrhea at any time during your treatment.
• tell your doctor if you are pregnant or plan to become pregnant. You should use birth control to prevent pregnancy during your treatment. Talk to your doctor about birth control methods that will work for you. If you become pregnant while taking zonisamide, call your doctor.
• tell your doctor if you are breast-feeding. If you breast-feed during your treatment, your baby may receive some zonisamide in the breast milk. Watch your baby closely for unusual sleepiness or poor weight gain.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking zonisamide.
• you should know that zonisamide may make you drowsy. Do not drive a car, operate machinery, or perform dangerous tasks until you know how this medication affects you.
• you should know that zonisamide can decrease the body's ability to sweat and make it harder for your body to cool down when it gets very hot. This happens most often in warm weather and to children who take zonisamide. (Children should not normally take zonisamide, but in some cases, it may be prescribed by a doctor.) You should avoid exposure to heat and call your doctor right away if you have a fever and/or are not sweating as usual.
• you should know that your mental health may change in unexpected ways and you may become suicidal (thinking about harming or killing yourself or planning or trying to do so) while you are taking zonisamide for the treatment of epilepsy, mental illness, or other conditions. A small number of adults and children 5 years of age and older (about 1 in 500 people) who took anticonvulsants such as zonisamide to treat various conditions during clinical studies became suicidal during their treatment. Some of these people developed suicidal thoughts and behavior as early as 1 week after they started taking the medication. There is a risk that you may experience changes in your mental health if you take an anticonvulsants medication such as zonisamide, but there may also be a risk that you will experience changes in your mental health if your condition is not treated. You and your doctor will decide whether the risks of taking an anticonvulsant medication are greater than the risks of not taking the medication. You, your family, or your caregiver should call your doctor right away if you experience any of the following symptoms: panic attacks; agitation or restlessness; new or worsening irritability, anxiety, or depression; acting on dangerous impulses; difficulty falling or staying asleep; aggressive, angry, or violent behavior; mania (frenzied, abnormally excited mood); talking or thinking about wanting to hurt yourself or end your life; withdrawing from friends and family; preoccupation with death and dying; giving away prized possessions; or any other unusual changes in behavior or mood. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.

What SPECIAL DIETARY instructions should I follow?

Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine.

Drink 6-8 glasses of water every day during your treatment with zonisamide.

What should I do IF I FORGET to take a dose?

Talk to your doctor about what to do if you miss a dose of zonisamide. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Zonisamide may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea
• vomiting
• weight loss
• changes in taste
• diarrhea
• constipation
• heartburn
• dry mouth
• headache
• dizziness
• confusion
• irritability
• difficulty falling asleep or staying asleep
• difficulty with memory
• pain, burning, numbness, or tingling in the hands or feet
• uncontrollable eye movements
• double vision

Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, call your doctor immediately:

• rash
• blistering or peeling of skin
• worsening or longer-lasting seizures
• sudden back pain
• stomach pain
• pain when urinating
• bloody or dark urine
• fever, sore throat, chills, cough, and other signs of infection
• sores in mouth
• easy bruising
• difficulty thinking of words or trouble speaking
• difficulty thinking or concentrating
• lack of coordination
• difficulty walking
• severe weakness
• severe muscle pain
• extreme tiredness
• loss of appetite
• fast, shallow breathing
• irregular heartbeat
• loss of consciousness

Zonisamide may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Zonisamide may cause metabolic acidosis (abnormally low levels of a certain natural substance in the blood). Metabolic acidosis that is left untreated for a long time may increase the risk that other medical problems, including kidney stones and bone problems that may lead to fractures, will develop. Untreated metabolic acidosis may also cause slowed growth and a decrease in final height in children. Talk to your doctor about the risks of taking zonisamide.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light, excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (https://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location — one that is up and away and out of their sight and reach. https://www.upandaway.org

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

• slow heartbeat
• slowed breathing
• dizziness
• fainting
• coma (loss of consciousness for a period of time)

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to zonisamide.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™. © Copyright, 2024. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: July 20, 2024.