About Lamotrigine Phenyltriazine derivative, Anticonvulsant,Mood stabilizer. Mechanism of Action of Lamotrigine Lamotrigine prolongs the inactivated state of voltage sensitive neuronal sodium ion channel either by increasing the efflux or decreasing the influx of sodium ion across the cell membrane and inhibits the high frequency firing of neurons. It blocks the voltage sensitive sodium ion channel and stabilizes the presynaptic membrane. It also prevents the release of excitatory neurotransmitters such as glutamate and aspartate receptors Interactions for Lamotrigine Phenytoin, carbamazepine, phenobarbitone and primidone: Enhance the metabolism of lamotrigine and may increase dose requirements. Sodium Valproate: Reduces the metabolism of lamotrigine. There is no evidence that lamotrigine causes clinically significant induction or inhibition of hepatic oxidative drug-metabolizing enzymes.