Lamotrigine is used alone or with other medications to prevent and control seizures. It may also be used to help prevent the extreme mood swings of bipolar disorder in adults. Lamotrigine is known as an anticonvulsant or antiepileptic drug. It is thought to work by restoring the balance of certain natural substances in the brain. This drug is not approved for use in children younger than 2 years due to an increased risk of side effects (such as infections).