Zonisamide (Zonegran) Side Effects

Possible side effects of zonisamide are listed below. Call your doctor for medical advice if these side effects are severe or continue after a few days once your body has adjusted to the medicine.

• Gastrointestinal side effects such as heartburn, nausea, vomiting, diarrhea, constipation
• Dry mouth
• Changes in taste
• Decreased appetite and weight loss
• Dizziness
• Headache
• Confusion
• Insomnia or trouble sleeping
• Mood changes such as irritability
• Memory problems
• Eye problems such as eye pain, double vision, or uncontrolled eye movements
• Numbness, tingling, burning, pain in the hands or feet

Rarely, zonisamide can cause more serious side effects. Tell your doctor right away or seek emergency medical attention if you develop:

• Serious skin reactions (skin rash, hives, itching, blistering, peeling skin)
• Worsening seizures (more frequent or longer-lasting seizures)
• Stomach pain
• Sudden back pain
• Painful or difficult urination
• Blood in urine, dark-colored urine
• Flu-like symptoms (fever, chills, sore throat, cough, unusual tiredness, and other signs of infection)
• Mouth ulcers or sores
• Unusual bleeding or bruising
• Speaking difficulty
• Problems with thinking, concentration, coordination, or walking
• Severe weakness, fatigue, or muscle pain
• Unusual drowsiness
• Irregular heartbeat
• Shallow or rapid breathing
• Trouble breathing
• Loss of appetite
• Loss of consciousness 

The above list may not include all the potential side effects of zonisamide. Contact your healthcare provider if your side effects are unusual or severe or do not get better over time. You can also report unusual side effects to the Food and Drug Administration at 1-800-FDA-1088.

Zonisamide (Zonegran) Overdose: In case of an overdose of zonisamide, call your doctor right away. You can also call your local poison control center or the national poison control center at 1-800-222-1222. Call 911 or emergency services if a person has collapsed, cannot breathe, has had a seizure, or cannot be awakened. Overdose symptoms may include slowed breathing, slowed heartbeat, dizziness, fainting, and loss of consciousness.

Source: FDA