Zonisamide is used with other medications to prevent and control seizures (epilepsy). Zonisamide is a sulfonamide anticonvulsant and a carbonic anhydrase inhibitor. It is unknown how zonisamide works to prevent seizures.
Read the Medication Guide provided by your pharmacist before you start taking zonisamide and each time you get a refill. If you have any questions, consult your doctor or pharmacist. Take this medication by mouth as directed by your doctor, usually 1 to 2 times a day with or without food. Swallow the capsules whole. To prevent kidney stones from forming, drink plenty of liquids while taking this medication unless your doctor instructs you otherwise. Dosage is based on your medical condition and response to treatment. It is very important to follow your doctor's dosing instructions exactly. Your doctor will start you on a low dose and slowly increase your dose. It may take several weeks or months to reach the best dose for you and to get the full benefit from this medication. Use this medication regularly to get the most benefit from it. This drug works best when the amount of medicine in your body is kept at a constant level. To help you remember and to keep a constant level, take zonisamide at the same time(s) each day. Do not stop taking this medication without consulting your doctor. Some conditions may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased. Tell your doctor if your condition does not improve or if it worsens.
Dizziness, drowsiness, trouble sleeping, lack of coordination, lightheadedness, loss of appetite, diarrhea, or double vision may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any unlikely but serious side effects, including: mental/mood problems (such as confusion, difficulty concentrating, memory problems, agitation, irritability), speech problems, decreased sweating, sudden back/side/abdominal pain, painful urination. A small number of people who take anticonvulsants for any condition (such as seizure, bipolar disorder, pain) may experience depression, suicidal thoughts/attempts, or other mental/mood problems. Tell your doctor right away if you or your family/caregiver notice any unusual/sudden changes in your mood, thoughts, or behavior including signs of depression, suicidal thoughts/attempts, thoughts about harming yourself. This medication may cause a serious metabolic problem (metabolic acidosis). Get medical help right away if you have any of the following symptoms: bone pain/breakage, rapid breathing, fast/irregular heartbeat, sudden/unexplained tiredness, severe drowsiness/difficulty staying awake. Get medical help right away if you have any very serious side effects, such as: easy bruising/bleeding, signs of kidney problems (such as change in the amount of urine, pink/bloody urine), signs of liver problems (such as nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine). A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug include: carbonic anhydrase inhibitors (such as acetazolamide), orlistat. Other medications can affect the removal of zonisamide from your body, which may affect how zonisamide works. Examples include other medications to treat seizures (such as phenobarbital, phenytoin, primidone), rifamycins (such as rifabutin), St. John's wort, among others. Your doctor may need to adjust your dose of zonisamide if you are on these medications. Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana (cannabis), antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and narcotic pain relievers (such as codeine). Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: slow/shallow breathing, severe dizziness, loss of consciousness.