Pharmacodynamic basis of gabapentin combined with Hegu-point catgut embedding for post-herpetic neuralgia

Background: Post-herpetic neuralgia (PHN) is a common refractory complication of herpes zoster, characterized by persistent neuropathic pain that seriously impairs patients’ quality of life. Objectives: The study aimed to assess the clinical effects of gabapentin when administered in combination with Hegu-point catgut embedding in patients suffering from post-herpetic neuralgia (PHN). Methods: A randomized, assessor-blinded study was conducted, wherein a total of 210 PHN patients were equally divided into two groups: 1) the control group receiving only gabapentin and 2) the combination group that received combined therapy of gabapentin and Hegu-point catgut embedding weekly. After 4 weeks of treatment, pain intensity, sleep quality, serum biomarkers, clinical efficacy and adverse events were evaluated. Results: After 4 weeks, both groups displayed a significant reduction in Visual Analogue Scale (VAS) and Pittsburgh Sleep Quality Index (PSQI) scores, with greater improvement reported in the combination group (P < 0.05). In addition, both groups showed a significant decrease in serum levels of substance P, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-?), while ?-endorphin levels showed a significant increase. The changes were found to be more pronounced in the combination group (P < 0.05). Interestingly, the combination group demonstrated a higher overall response rate (92.38% vs 80.00%) and fewer adverse events (12.38% vs 26.67%, P < 0.05). Conclusion: Altogether, combination therapy provided superior short-term improvement in symptoms and biomarker modulation as compared to gabapentin alone. Since the present study only assessed peripheral serum markers, the underlying mechanistic pathways could not be deciphered. Additionally, longer-term outcomes of therapy were not assessed, serving as a major limitation of this study.