Evaluation of Efficacy and Safety of OXC XR as Adjunctive Therapy for Partial Seizures

Inclusion Criteria: * Capable of complying with the study procedures. * Able to provide written informed consent * Male or female aged 18 to 65 years, inclusive. * Diagnosis of partial onset seizures * Minimum of three seizures per 28 days * Receiving treatment with 1-3 AEDs * Refractory to at least one AED * No progressive neurological conditions by recent MRI/CT * Adequate birth control in women of child-bearing potential Exclusion Criteria: * Refractory to OXC for reasons of efficacy * Recent status epilepticus * Recent non-epileptic seizures * Current diagnosis of major depression * Recent suicidal plan or intent or more than one attempt * Current use of oxcarbazepine, felbamate for \< 18 months, phenytoin with levels \>15mcg/mL or frequent need for rescue benzodiazepines * Current use of sodium-lowering non-seizure medications. * Clinically significant hepatic, renal, or cardiovascular function * History of recent substance abuse * Females who are pregnant or lactating. * Hypersensitivity to OXC or related drugs * Difficulty swallowing study medication