An article on Lamotrigine (Lamictal) touching on mechanism of action. The context is an unusual use, in schizophrenia.
Update 3-29: The drug MOA appears to be inhibition of voltage dependent Na+ channels. This increases NMDA receptor glutamate transmission apparently. For those allergic to Lamictal, carbamazepine has a similar mechanism of action but the clinical data is limited, mixed, negative in a double blind study. The key reference is Large CH, Webster EL, Goff DC. Psychopharmacology 18: 415-436, SEP 2005. Oxcarbazepine (Trileptal) is a more potent inhibitor of the channels than the earlier drug carbamazepine