Lamotrigine

Lamotrigine is a novel anticonvulsant drug for inhibition of 5-hydroxytryptamine (5-HT) uptake in both human platelets and rat brain synaptosomes with IC50 of 240 μM and 474 μM, respectively. Lamotrigine inhibits the synaptosomal uptake of noradrenaline and dopamine with IC50 of 239 μM and 322 μM, respectively. Lamotrigine is believed to mediate its anticonvulsant activity by the use- and voltage-dependent blockade of Na+ channels. Lamotrigine may also be useful in the treatment of bipolar illness with efficacy against depressive breakthroughs and rapid cycling bipolar disorder. The reduction in the uptake of label caused by 1 mM lamotrigine incubated in the presence of 10 nM 5-HT is reversed by increasing the substrate concentration 10-fold. The inhibition of the p-chloroamphetamine-induced 5-HT syndrome in rats suggests that lamotrigine also inhibits 5-HT uptake. Lamotrigine is a new generation broad-spectrum anticonvulsant.