What is zonisamide-oral, and how does it work (mechanism of action)?

  • Scientists do not known how exactly zonisamide works in the body. Zonisamide is presumed to work on the sodium and calcium channels in the brain cells where it controls electric-currents that are responsible for seizure activity.
  • The FDA approved zonisamide in March 2000.
  • The brand name for zonisamide is Zonergran.
  • Zonisamide is available in generic form. You need a prescription to obtain zonisamide.

What is zonisamide-oral used for?

Zonisamide (Zonergan) is an anti-seizure medication. Zonisamide is primarily used to treat partial-seizures.

What are the side effects of zonisamide-oral?

Common side effects of zonisamide are:

Serious side effects of zonisamide include:

  • Psychiatric disorders such as schizophrenia
  • Seizures
  • Serious skin disorders such as Stevens-Johnson's syndrome or toxic epidermal necrolysis.


If you have had a seizure, it means you have epilepsy. See Answer

What is the dosage for zonisamide-oral?

The recommended starting dose of zonisamide is 100 mg/day. Doses may be increased 100 mg/day every 2 weeks. The usual dosage varies from 100 to 600 mg/day, administered in 1 to 2 divided doses.

Safe and effective use of zonisamide is not established for children under the age of 16.

Which drugs or supplements interact with zonisamide-oral?

Zonisamide increases the risk of lactic acid build up when combined with metformin (Glucophage). If you experience sudden weakness, heavy breathing, and increased drowsiness, contact your healthcare professional immediately.

Orlistat (Xenical) should be used with caution with zonisamide because it lowers the beneficial effects of zonisamide and increases the chances of seizures. If you experience dizziness, drowsiness, difficulty walking, nausea, vomiting, and abnormal eye movements, contact your healthcare professional immediately.

Is zonisamide-oral safe to take if you are pregnant or breastfeeding?

  • There are no adequate studies done on zonisamide to determine its safe and effective use in pregnant mothers.
  • It is not known whether zonisamide is excreted in breast milk. It should be used with caution in females who are nursing.

What else should I know about zonisamide-oral?

What preparations of zonisamide-oral are available?

Capsules: 25, 50, and 100 mg.

How should I keep zonisamide-oral stored?

Store zonisamide capsules between 20 C and 25 C (68 F and 77 F).


Zonisamide (Zonegran) is a prescription drug prescribed as supplemental therapy in treating partial seizures. Side effects, drug interactions, dosing and storage information, and pregnancy safety should be reviewed prior to taking this medication.

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Medically reviewed by John P. Cunha, DO, FACOEP
FDA Prescribing Information.