Partial seizures

Active Ingredient: Zonisamide

Indication for Zonisamide

Population group: only adults (18 years old or older)

Zonisamide is indicated as:

  • monotherapy in the treatment of partial seizures, with or without secondary generalisation, in adults with newly diagnosed epilepsy;
  • adjunctive therapy in the treatment of partial seizures, with or without secondary generalisation, in adults, adolescents, and children aged 6 years and above.

For this indication, competent medicine agencies globally authorize below treatments:

100-500 mg once a day

Route of admnistration


Defined daily dose

50 - 500 mg

Dosage regimen

From 50 To 500 mg once every day

Detailed description

Zonisamide may be taken as monotherapy or added to existing therapy in adults. The dose should be titrated on the basis of clinical effect. Recommended escalation and maintenance doses are given in Table 1. Some patients, especially those not taking CYP3A4-inducing agents, may respond to lower doses.


When zonisamide treatment is to be discontinued, it should be withdrawn gradually. In clinical studies of adult patients, dose reductions of 100 mg at weekly intervals have been used with concurrent adjustment of other antiepileptic medicine doses (where necessary).

Table 1. Adults – recommended dosage escalation and maintenance regimen:

Treatment Regimen Titration PhaseUsual Maintenance Dose
Newly diagnosed adult patientsWeek 1 + 2 Week 3 + 4 Week 5 + 6 300 mg per day (once a day). If a higher dose is required: increase at two-weekly intervals in increments of 100 mg up to a maximum of 500 mg.
100 mg/day (once a day) 200 mg/day (once a day) 300 mg/day (once a day)
Adjunctive therapy
- with CYP3A4-inducing agents (see section 4.5) Week 1 Week 2 Week 3 έως 5 300 to 500 mg per day (once a day or two divided doses).
50 mg/day (in two divided doses) 100 mg/day (in two divided doses) Increase at weekly intervals in increments of 100 mg
- without CYP3A4-inducing agents; or with renal or hepatic impairmentWeek 1 + 2 Week 3 + 4 Week 5 to 10 300 to 500 mg per day (once a day or two divided doses). Some patients may respond to lower doses.

Dosage considerations

Zonisamide may be taken with or without food.

Active ingredient


Zonisamide is a benzisoxazole derivative with antiepileptic and anticonvulsant activity. The mechanism of action of zonisamide is not fully elucidated, but it appears to act on voltage-sensitive sodium and calcium channels, thereby disrupting synchronised neuronal firing, reducing the spread of seizure discharges and disrupting subsequent epileptic activity.

Read more about Zonisamide

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