Lamotrigine (marketed as Lamictal by GlaxoSmithKline, called Lamictin in South Africa, (Lamogine) in Israel, and in South Korea) is an anticonvulsant drug used in the treatment of epilepsy and bipolar disorder. For epilepsy it is used to treat partial seizures, primary and secondary tonic-clonic seizures, and seizures associated with Lennox-Gastaut syndrome. Lamotrigine also acts as a mood stabilizer. It is the first medication since lithium granted Food and Drug Administration (FDA) approval for the maintenance treatment of bipolar type I. Chemically unrelated to other anticonvulsants, lamotrigine has relatively few side-effects and does not require blood monitoring. The exact way lamotrigine works is unknown. Some think that it is a Na+ channel blocker. It is inactivated by hepatic glucuronidation.

Lamotrigine has been successful in controlling rapid cycling and mixed bipolar states in people who have not received adequate relief from lithium, carbamazepine and/or valproate, possibly having significantly more antidepressant potency than either carbamazepine or valproate. It is useful as part of the treatment of some people with major (unipolar) depression, and has recently been reported to be a useful treatment for some people with post-traumatic stress disorder (PTSD) and borderline personality disorder (BPD). (Source: Lamotragine FAQ.).