Assessing The Long-Term Safety And To Explore The Long-Term Efficacy Of Zonisamide As Monotherapy In Newly Diagnosed Partial Seizures

Inclusion Criteria: 1. Subject has completed study E2090-E044-310. 2. Subject is able and willing to give written informed consent. 3. Female subjects without childbearing potential (two years post-menopausal, bilateral oophorectomy or tubal ligation, complete hysterectomy) are eligible. Female subjects of childbearing potential must be non-pregnant, non-lactating and abide by one of the following medically acceptable contraceptive measures: oral contraceptive pill, contraceptive injections, implants or patches, intrauterine device in place for at least three months, vasectomised partner or abstinence throughout the study and for one month after discontinuation of study medication. When the contraceptive pill is used, this should contain no less than 50 μg oestrogen. 4. The subject is able and willing to follow the investigational study procedures, maintain a seizure diary and report adverse events. Exclusion Criteria: 1. Subject has a history of a significant or currently uncontrolled disease that will contraindicate the use of the study drugs or interfere with the conduct of this study and/or the assessment of safety and efficacy of the study drugs. 2. Subject has a body weight \<40 kg. 3. Subject has a newly occurring progressive malignancy during study E2090-E044-310 (excluding a history of non-metastasized and adequately treated cutaneous squamous cell carcinoma). 4. Subject has developed a psychiatric illness or mood disorder requiring electro-convulsive or drug therapy within the previous 6 months and is considered uncontrolled; history of suicide attempt, alcohol or drug abuse, chronic treatment with benzodiazepines or barbiturates. 5. Subject is currently taking carbonic anhydrase inhibitors. 6. Subject developed pancreatitis, nephrolithiasis or hypercalcuria, clinically significant laboratory abnormalities, stroke or uncontrolled hypertension during study E2090-E044-310. 7. Subject is currently taking monoamine oxidase inhibitors (MAOIs) or any other excluded medications (see protocol section 9.9.3). 8. Subject has a history of allergy to carbamazepine or to zonisamide or to any of their ingredients or to sulphonamides. 9. Subject has developed a bone marrow depression, low platelet count or other blood dyscrasias.