ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.
Overview
It's a sulfa-type medicine.
What it's used for
- Partial (focal) seizures (with other medicines)
How to take it
- Swallow capsules whole.
- Drink plenty of fluids to lower kidney stone risk.
- Don't stop suddenly.
Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.
Side effects
Common side effects
- Sleepiness
- Dizziness
- Less appetite
- Trouble concentrating
Call 911A blistering, peeling, or widespread red rash, especially with fever
Call your provider todayNot sweating with a high body temperature, especially in children
Call your provider todaySide or back pain or blood in urine
Call 911Thoughts of suicide or harming yourself. Call or text 988 any time.
Warnings
- Not for people allergic to sulfa drugs.
Other medicines, foods, and alcohol
- Carbamazepine and phenytoin lower its level.
- Topiramate adds to kidney stone and acid risk.
Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.
Pregnancy and breastfeeding
Talk with your provider.
Missed doses, overdose, and storage
If you miss a dose
Take it as soon as you remember, unless it's almost time for your next dose. Then skip the missed dose. Don't take two doses at once.
If someone takes too much
Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.
Storing it
Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.
Conditions it's used for
Sources
- DailyMed: FDA drug label for Zonisamide (U.S. National Library of Medicine)
- MedlinePlus: Drugs, herbs, and supplements
- FDA: Drugs@FDA
Last updated 2026-11-13.