Post-Herpetic Neuralgia (PHN)

The purpose of this study is to evaluate the therapeutic efficacy of transcutaneous auricular vagus nerve stimulation (taVNS) in the treatment of patients with post-herpetic neuralgia (PHN). Participants will receive taVNS in addition to standard care. The study aims to determine whether taVNS can provide significant pain relief and improve quality of life in PHN patients.

Post-herpetic neuralgia (PHN) is the most significant complication of herpes zoster caused by reactivation of latent Varicella-Zoster virus (VZV). PHN is characterized by neuropathic pain lasting beyond the resolution of the rashes. Post herpetic neuralgia (PHN) represents a potentially debilitating and often undertreated form of neuropathic pain that disproportionately affects vulnerable populations, including the elderly and the immunocompromised. PHN pain is typically localized, unilateral and chronic, but may be constant, intermittent, spontaneous and/or evoked. PHN is likely to interfere with sleep and daily activities. Pregabalin is a gabapentinoid licenced for treatment of neurological disorders. It is one of the earlier drugs approved by the US Food and Drug Administration (2004) for the treatment of painful diabetic neuropathy and postherpetic neuralgia (PHN). Lacosamide (LCM) was approved in 2008 in the European Union and in the United States as adjunctive therapy for the treatment of focal-onset seizures with or without secondary generalization in adults and adolescents with epilepsy. Its efficacy has also been proven in neuropathic pain. Although Pregabalin and Lacosamide have proven effective in various neuropathic pain disorder, comparative studies specifically for PHN remain scarce. This study aims to compare the efficacy of Pregabalin and Lacosamide in PHN patients, addressing the current gap in literature and providing clinically relevant insights to optimize treatment selection.