Oxcarbazepine (Trileptal) is used to treat partial-onset seizures (also called focal aware seizures). This antiepileptic is for people 2 years of age and older. It helps calm the brain to keep seizures from happening. Oxcarbazepine (Trileptal) comes as immediate-release tablets and an oral suspension. You take it by mouth twice a day. Some common side effects include dizziness, nausea, and headaches. Immediate-release oxcarbazepine comes in both brand-name and generic versions. You can take it by itself or with other anti-seizure medications.