The purpose of this study is to acquire additional information about the appropriate level of dosing of Zonisamide when it is prescribed for patients with partial onset epileptic crisis who are already being treated with two other antiepileptic drugs.

Patients from both sexes, 18 to 65 years of age, diagnosed with simple or complex partial onset epileptic crisis defined according to the International League Against Epilepsy (ILAE) criteria, with a minimum of two seizures within the 4 previous weeks, a stable treatment with two antiepileptic drugs for at least 12 weeks, and capable and willing to give their informed consent, will be included in the study.

To these patients, physicians will prescribe zonisamide in the following manner: Titration period of 12 weeks, at the end of which all patients must be taking 300 mg. Maintenance doses period of 12 weeks, at the beginning of which, physicians will decide to keep the 300 mg dose from the titration period, lower it to 200 mg, or take it up to 400 mg. Six weeks later within this period, a decision will be made to raise the 400 mg doses up to 500 mg if considered necessary and tolerable.

Drugs will be prescribed by the physician and purchased by the patient.

Inclusion Criteria:

Patients from both sexes, 18 to 65 years of age, diagnosed with simple or complex partial onset epileptic seizures defined according to the International League Against Epilepsy (ILAE) criteria, with a minimum of two crises within the 4 previous weeks, a stable treatment with two antiepileptic drugs for at least 12 weeks and capable and willing to give their informed consent, will be included.

Exclusion Criteria:

Those who do not fulfill the Inclusion requirements.