Lamotrigine treats epilepsy (partial seizures primary generalized tonic-clonic seizures Lennox-Gastaut syndrome) bipolar I disorder maintenance and off-label conditions like acute bipolar depression and fibromyalgia.

It stabilizes neuronal membranes by inhibiting voltage-sensitive sodium channels suppressing excitatory neurotransmitter release (e.g. glutamate) and modulating calcium channels to prevent seizures and mood episodes.

It features a triazine core substituted with two chlorophenyl groups and an aminotriazole moiety appearing as a white to pale yellow powder that is sparingly soluble in water.