SCN8A and trigeminal neuralgia: Carbamazepine and lamotrigine are effective in trigeminal neuralgia [63] because they shift the steady-state inactivation of NaV channels, including NaV1.3 and NaV1.6, to more hyperpolarized potentials [64], counteracting the loss of long-term inactivation [65] in the trigeminal nerve.