Figure 2. Anticonvulsants like phenytoin (left), carbamazepine (middle) and Lamotrigine (right) share common molecular structures. They are tricyclic compounds that form interactions with the inner pore of the channel, specifically in Domain IV and the S6 helix. The two biding sites that these compounds share with local anesthetics in DIV-S6 are Phe-1764 and Tyr-1771. The interactions include aromatic-aromatic interactions and aromatic-polar interactions. However there are additional interactions formed elsewhere that helps block the pore (for a review see ref. 28). Image from reference 28.