The anticonvulsant lacosamide (R-2-acetamido-N-benzyl-3-methoxypropionamide), which is FDA-approved for the treatment of epilepsy, has been investigated as a potential treatment for diabetic neuropathic pain (Shaibani et al., 2009; Wymer et al., 2009; Ziegler et al., 2010), refractory pain (McCleane et al., 2003), and recently, NaV1.7-related painful small fiber neuropathy (de Greef et al., 2019), among others (Carona et al., 2021). This evidence concerns the gene SCN9A and neuropathy, small fiber.