A Study for Evaluating the Efficacy and Safety of Zonisamide and Lamotrigine (Lamictal) for Subjects With Refractory Simple Partial, Complex Partial or Partial With Secondary Generalized Seizures

Inclusion criteria: * Subjects must sign and date the informed consent form * Clinical diagnosis as refractory epilepsy Exclusion criteria: * Progressive neurologic disease * Serious psychiatric disease * Hemolytic anemia * G6PD (glucose-6-phosphate dehydrogenase) deficiency * Acute intermittent porphyrias * Subjects who have received study drugs (Zonisamide, Lamotrigine) in the past * Drug or alcohol addiction * Renal impairment (serum creatinine ≧ 1.5 mg/dl), or hepatic abnormality (ALT or AST \> 2x ULN) * Stevens-Johnson syndrome * Progressive exfoliative dermatitis * Pregnant, lactating or of childbearing potential female * Regularly taking oral contraceptives * Hypersensitivity to study drugs * Severe cardiac disease (New York Heart Association Functional Class III and IV) * History of malignancy within 5 years * Taking valproic acid within 7 days prior to screening * Subjects with simple partial seizures without motor component