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Zonegran Side Effects

Generic Name: zonisamide

Note: This document contains side effect information about zonisamide. Some of the dosage forms listed on this page may not apply to the brand name Zonegran.

For the Consumer

Applies to zonisamide: oral capsule, oral tablet

Along with its needed effects, zonisamide (the active ingredient contained in Zonegran) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking zonisamide:

More common
  • Discouragement
  • feeling sad or empty
  • irritability
  • lack of appetite
  • loss of interest or pleasure
  • mood or mental changes
  • shakiness or unsteady walking
  • tiredness
  • trouble with concentrating
  • trouble with sleeping
Less common
  • Agitation
  • bruising
  • delusions
  • hallucinations
  • large, flat blue or purplish patches on the skin
  • rash

Some side effects of zonisamide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Abdominal or stomach pain
  • anxiety
  • difficulty with memory
  • dizziness
  • double vision
  • headache
  • loss of appetite
  • nausea
  • restlessness
  • sleepiness
  • unusual drowsiness
  • unusual tiredness or weakness
Less common
  • Aching muscles or joints
  • acid or sour stomach
  • bad, unusual, or unpleasant taste in the mouth
  • belching
  • change in taste
  • chills
  • constipation
  • diarrhea
  • difficulty with speaking
  • difficulty with thinking
  • dry mouth
  • fever
  • general ill feeling
  • headache
  • heartburn
  • indigestion
  • mental slowness
  • nervousness
  • runny or stuffy nose
  • sneezing
  • tingling, burning, or prickly feelings on the skin
  • uncontrolled, back and forth, or rolling eye movements
  • weight loss

For Healthcare Professionals

Applies to zonisamide: oral capsule


The most common adverse reactions to this drug are somnolence, dizziness, and anorexia.[Ref]


Very common (10% or more): Anorexia (13%)
Common (1% to 10%): Abdominal pain, nausea, diarrhea, dyspepsia, constipation, dry mouth[Ref]

Nervous system

Very common (10% or more): Somnolence (17%), dizziness (13%), headache (10%), ataxia
Common (1% to 10%): Paresthesia, fatigue, tiredness, bradyphrenia, tremor
Uncommon (0.1% to 1%): Convulsion
Very rare (less than 0.01%): Coma, grand mal seizure, myasthenic syndrome, neuroleptic malignant syndrome, status epilepticus
Postmarketing reports: Restless legs syndrome[Ref]


Common (1% to 10%): Speech abnormalities, difficulties in verbal expression, taste perversion[Ref]


Very common (10% or more): Agitation, irritability, confusional state, depression
Common (1% to 10%): Difficulty concentrating, difficulty with memory, mental slowing, insomnia, anxiety, nervousness, affect liability, psychotic disorder
Uncommon (0.1% to 1%): Anger, aggression, suicidal ideation, suicide attempt
Very rare (less than 0.01%): Hallucination, amnesia, mania[Ref]


Common (1% to 10%): Nystagmus, diplopia[Ref]


Common (1% to 10%): Rash
Very rare (less than 0.01%): Drug rash with eosinophilia and systemic symptoms, anhidrosis, erythema multiforme, pruritus, Stevens-Johnson syndrome, toxic epidermal necrolysis[Ref]


Very common (10% or more): Anorexia
Common (1% to 10%): Weight loss
Very rare (less than 0.01%): Metabolic acidosis
Postmarketing reports: Elevated creatine phosphokinase[Ref]


Common (1% to 10%): Ecchymosis
Very rare (less than 0.01%): Agranulocytosis, aplastic anemia, leukocytosis, leucopenia, lymphadenopathy, pancytopenia, thrombocytopenia[Ref]


Common (1% to 10%): Rhinitis
Uncommon (0.1% to 1%): Pneumonia[Ref]


Uncommon (0.1% to 1%): Urinary tract infection
Postmarketing reports: Acute pancreatitis[Ref]


Postmarketing reports: Rhabdomyolysis[Ref]


Uncommon (0.1% to 1%): Urinary tract infection[Ref]


Common (1% to 10%): Hypersensitivity
Very rare (less than 0.01%): Drug induced hypersensitivity syndrome[Ref]


Common (1% to 10%): Influenza syndrome[Ref]


Very rare (less than 0.01%): Renal tubular acidosis
Frequency not reported: Nephrolithiasis, hydronephrosis, renal failure, urine abnormality[Ref]


1. "Product Information. Zonegran (zonisamide)" Elan Pharmaceuticals, S. San Francisco, CA.

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online. Available from: URL:" ([2006]):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.