This page presents data from the FDA Adverse Event Reporting System (FAERS) and the FDA-approved drug label. A report submitted to FAERS does not prove a drug caused the reported event. Always consult a healthcare provider about medications.
Zonisamide is a medication, a anti-epileptic agent. According to the FDA-approved label, Zonisamide capsules are indicated as adjunctive therapy in the treatment of partial seizures in adults with epilepsy. FAERS contains 10,560 submissions naming this drug from 2004 through 2026; the top three reactions cited are drug ineffective, seizure, and off label use.
Most-Reported Reactions
Counts of the reactions most often cited in FAERS submissions that named Zonisamide. Inclusion here does not establish causation - submitters describe what was observed, not what was confirmed. One submission can list several reactions, so the totals exceed the report count.
Patient Demographics
Patient sex and age across the FAERS submissions that named Zonisamide. Percentages here are computed only from submissions where these fields were filled in - many leave them blank.
By Sex
By Age Group
Severity Outcomes
Severity flags recorded across the 10,560 FAERS submissions that named Zonisamide. Each bar shows the count of those reports carrying that flag. A single case can carry more than one (a hospitalization that became life-threatening, for example), so these bars are independent rates - they don't sum to 100%. Inclusion of a case under any flag does not establish that the drug caused the outcome.
Submissions Per Quarter
Quarterly count of FAERS submissions that named Zonisamide. Ups and downs on this chart can track prescribing volume, news cycles, or shifts in how reports get filed, rather than the drug becoming safer or more dangerous.
From the FDA-Approved Label
Excerpts from the official FDA-approved prescribing information for Zonisamide. This is the authoritative source on indications, warnings, and known adverse reactions.
Indications
Zonisamide capsules are indicated as adjunctive therapy in the treatment of partial seizures in adults with epilepsy.
Warnings
Potentially Fatal Reactions to Sulfonamides: Fatalities have occurred, although rarely, as a result of severe reactions to sulfonamides (zonisamide is a sulfonamide) including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias. Such reactions may occur when a sulfonamide is readministered irrespective of the route of administration. If signs of hypersensitivity or other serious reactions occur, discontinue zonisamide immediately. Specific experience with sulfonamide-type adverse reaction to zonisamide is described below. Serious Skin Reactions Consideration should be given to discontinuing zonisamide in patients who develop an otherwise unexplained rash. If the drug is not discontinued, patients should be observed frequently. Seven deaths from severe rash [i.e., Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)] were reported in the first 11 years of marketing in Japan. All of the patients were receiving other drugs in addition to zonisamide. In post-marketing experience from Japan, a total of 49 cases of SJS or TEN have been reported, a reporting rate of 46 per million pat...
Adverse Reactions (from label)
The most common adverse reactions with zonisamide (an incidence at least 4% greater than placebo) in controlled clinical trials and shown in descending order of frequency were somnolence, anorexia, dizziness, ataxia, agitation/irritability, and difficulty with memory and/or concentration. In controlled clinical trials, 12% of patients receiving zonisamide as adjunctive therapy discontinued due to an adverse reaction compared to 6% receiving placebo. Approximately 21% of the 1,336 patients with epilepsy who received zonisamide in clinical studies discontinued treatment because of an adverse reaction. The most common adverse reactions leading to discontinuation were somnolence, fatigue and/or ataxia (6%), anorexia (3%), difficulty concentrating (2%), difficulty with memory, mental slowing, nausea/vomiting (2%), and weight loss (1%). Many of these adverse reactions were dose-related (see WARNINGS and PRECAUTIONS ) . Adverse Reaction Incidence in Controlled Clinical Trials Table 4 lists adverse reactions that occurred in at least 2% of patients treated with zonisamide in controlled clinical trials that were numerically more common in the zonisamide group. (continues in label)
AdverseEvent.ai is not affiliated with the FDA. Adverse-event counts come from the FDA Adverse Event Reporting System (FAERS). Drug labels come from the FDA drug label dataset. A report submitted to FAERS does not prove a drug caused the reported event — always consult a healthcare provider about medications. This site is for informational purposes only and is not medical advice.
