Lamotrigine is an open-channel blocker of the nicotinic acetylcholine receptor.

Lamotrigine is an antiepileptic drug employed in the treatment of partial epilepsies. We studied its possible interaction with channels other than its known therapeutic target, the voltage-gated sodium channel, using the adult muscle nicotinic acetylcholine receptor as a model system. At the single-channel level, lamotrigine caused a dose-dependent (a) diminution in mean open time, (b) increase in mean burst duration and (c) increase in the area of a new closed-time component. A simple linear channel blocking mechanism accounts for these results. Thus, lamotrigine exerts a blocking action on the muscle nicotinic acetylcholine receptor.