Zonisamide (Zonegran®)

Zonisamide (Zonegran®) Seizure Medication for Dogs & Cats

Zonisamide (Zonegran®) is an anticonvulsant medication used to reduce the frequency and severity of seizures in pets. No seizure medication can guarantee complete seizure freedom, but the goal is to make seizures less frequent and less severe.

Zonisamide Dosing & Administration

Give zonisamide on a consistent schedule, which is usually twice daily, with or without food. Set reminders and plan refills early when possible to ensure dosing is consistent.

Always follow the prescription label and the plan your pet’s veterinary team provides.

Missed Doses & Changing Medications

Consistency matters with seizure medications, and stopping suddenly can provoke seizures. If your pet misses a single dose of zonisamide, give it as soon as you remember, even if it’s time for the next dose.

Do not stop zonisamide or change the dose without veterinary guidance, as seizure medications generally require tapering before discontinuation. Your pet’s veterinary team may recommend a different approach for very short courses or if serious side effects occur.

Monitoring & Lab Work

Schedule regular veterinary visits at least twice a year to review seizure control and response to zonisamide. A complete blood count (CBC), chemistry panel, and urinalysis are also recommended annually.

If bringing a urine sample from home on the day of the appointment, use a clean disposable container and collect the sample as close to the appointment time as possible. If collecting in the hospital instead, try to prevent your pet from urinating right before the visit to help with collection.

Potential Side Effects of Zonisamide

Many pets tolerate zonisamide well, but side effects can occur. Contact your pet’s veterinary team if concerns come up, especially if symptoms feel significant or persistent.

  • Sedation and incoordination: Your pet may seem sleepy or unsteady, especially during the initial adjustment period. Keep them away from hazards such as stairs and pools until coordination improves.

  • Gastrointestinal issues: Inappetence and vomiting can occur. If appetite significantly decreases, an alternative medication may be necessary.

  • Urinary pH changes: Zonisamide can alter urine pH and may contribute to urinary stones. Annual urinalysis helps monitor for this, and your veterinary team may recommend diet changes or medication adjustments if needed.

  • Liver and blood cell changes: Liver dysfunction and changes in blood cell counts are rare, and annual blood tests help monitor for these effects.

  • Behavior changes: Watch for increased restlessness or aggression.

  • Dermatologic issues: Itching or skin lesions are rare, but contact your pet’s veterinary team if any skin changes appear.

Zonisamide (Zonegran®) FAQs

  • Zonisamide is a seizure medication used to reduce the frequency and severity of seizures. The goal is improved seizure control, even though complete seizure freedom is not guaranteed.

  • Zonisamide is usually given twice a day, either with or without food. Always follow the prescription label and the plan your pet’s veterinary team provides.

  • If your pet misses a dose of zonisamide, give it as soon as you remember, even if it’s time for the next dose, because stopping suddenly can provoke seizures. Contact your pet’s veterinary team if questions come up about timing.

  • Veterinary visits are recommended at least twice a year. A complete blood count (CBC), chemistry panel, and urinalysis are recommended annually.

  • Possible side effects include sleepiness or unsteadiness, decreased appetite or vomiting, changes in urine pH that may contribute to urinary stones, and rarely liver or blood cell changes. Behavior or skin changes can also occur. Contact your pet’s veterinary team if you have any concerns.