What are common side effects of oxcarbazepine (trileptal)?

Headache plus: Common side effects include headache, fatigue, and stomach upset (nausea). These are often present in the beginning or after a dose change. The higher the dose, the more likely they occur. Low sodium in the blood is common in older people and in others who take other medications that have a tendency to do the same. Sodium levels should be monitored. In general, Trileptal is a safe drug.