Zonisamide (patient information)

Why is this medication prescribed

Zonisamide is used in combination with other medications to treat seizures in adults with epilepsy. Zonisamide is in a class of medications called anticonvulsants. It works by decreasing abnormal excitement 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 around the same time 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 than once every 2 weeks.

Zonisamide controls epilepsy but does 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. If you suddenly stop taking zonisamide, your seizures may become worse. Your doctor will probably decrease your dose gradually.

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, celecoxib (Celebrex), 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. Be sure to mention any of the following: antifungals such as fluconazole (Diflucan), itraconazole (Sporanox), and ketoconazole (Nizoral); antihistamines; carbamazepine (Carbatrol, Tegretol), cimetidine (Tagamet); clarithromycin (Biaxin); cyclosporine (Neoral, Sandimmune); danazol (Danocrine); delavirdine (Rescriptor); dexamethasone (Decadron, Dexpak), diltiazem (Cardizem, Dilacor, Tiazac); ethosuximide (Zarontin), erythromycin (E.E.S., E-Mycin, Erythrocin); fluoxetine (Prozac, Sarafem); fluvoxamine (Luvox); HIV protease inhibitors such as indinavir (Crixivan) and ritonavir (Norvir); ipratropium (Atrovent); isoniazid (INH, Nydrazid); medications for irritable bowel disease, motion sickness, Parkinson's disease, ulcers, or urinary problems; metronidazole (Flagyl); nefazodone (Serzone); oral contraceptives (birth control pills); oral medications for glaucoma such as acetazolamide (Diamox); phenobarbital (Luminal, Solfoton); phenytoin (Dilantin); primidone (Mysoline); rifabutin (Mycobutin), rifampin (Rifadin, Rimactane); troglitazone (Rezulin); troleandomycin (TAO); valproic acid (Depakene, Depakote); verapamil (Calan, Covera, Isoptin, Verelan); and zafirlukast (Accolate). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had liver or kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking zonisamide, call your doctor. Zonisamide may harm the fetus.
• 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 or operate machinery until you know how this medication affects you.
• remember that alcohol can add to the drowsiness caused by this medication.
• you should know that you may be more likely to develop kidney stones while taking zonisamide. You should drink 6-8 glasses of water daily to help prevent kidney stones from forming.
• you should know that zonisamide can prevent you from sweating 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, a doctor will decide whether it is the best choice.) You should avoid exposure to heat and notify your doctor if you have a fever and/or are not sweating as usual.

What special dietary instructions should I follow

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

What should I do if I forget a dose

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Side effects

Mild side effects

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

• drowsiness
• loss of appetite
• upset stomach
• vomiting
• weight loss
• changes in taste
• dizziness
• constipation
• dry mouth
• headache
• confusion
• irritability
• difficulty falling asleep or staying asleep
• difficulty with memory
• pain, burning, or tingling in the hands or feet
• difficulty focusing eyes
• double vision
• sneezing
• runny nose

Severe side effects

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

• rash
• worsening or longer lasting seizures
• sudden back pain
• stomach pain
• pain when urinating
• bloody or dark urine
• fever
• sore throat
• sores in mouth
• easy bruising
• depression
• unusual thoughts
• difficulty thinking of words or trouble speaking
• difficulty thinking or concentrating
• lack of coordination
• difficulty walking

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

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 [at http://www.fda.gov/MedWatch/report.htm] or by phone [1-800-332-1088].

What storage conditions are needed for this medicine

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 excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include:

• slow heartbeat
• difficulty breathing
• dizziness
• fainting
• loss of consciousness

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.

Brand names

• Zonegran®