Cooling the Burn: EMLA Alone vs Paravertebral Block Plus EMLA for Improving Tolerability of 8% Capsaicin Patch Application in Thoracic Postherpetic Neuralgia – A Retrospective Cohort Study

Hassan A Moria^*

• University of Tabuk, Tabuk, Saudi Arabia

Background: The 8% capsaicin patch (Qutenza®) is an effective localized treatment for postherpetic neuralgia (PHN), yet intense application-related burning pain remains a major barrier to its broader use. Optimizing procedural tolerability is particularly important in elderly patients who are vulnerable to systemic analgesic side effects. Thoracic paravertebral block (TPVB) provides segmental analgesia and may attenuate procedural pain during capsaicin patch application. Objective: To compare procedural tolerability and short-term analgesic outcomes of topical EMLA alone versus EMLA combined with TPVB before 8% capsaicin patch application in patients with thoracic PHN. Methods: This retrospective cohort study included adults with thoracic PHN treated with 8% capsaicin patches at Prince Fahd bin Sultan Hospital, Tabuk, Saudi Arabia, between January 2022 and February 2025. Patients received either EMLA alone (n = 9) or EMLA plus ultrasound-guided TPVB (n = 8). The primary outcome was procedural tolerability, assessed using peak intraprocedural Numeric Pain Rating Scale (NPRS), area under the curve of NPRS over 60 minutes (AUC-NPRS), and need for intravenous (IV) tramadol. Secondary outcomes included NPRS at 8, 24, and 48 hours; change in Pittsburgh Sleep Quality Index (PSQI); oral tramadol use over 48 hours; and patient-reported acceptability. Results: Baseline characteristics were comparable between groups. Patients who received TPVB demonstrated markedly superior procedural tolerability compared with those pretreated with EMLA alone. Intraprocedural pain was substantially reduced, with a markedly lower cumulative pain burden and no requirement for IV rescue in the TPVB group, whereas all EMLA patients required opioid rescue and reported intense burning pain during application. Post-procedural pain scores remained consistently lower in the TPVB group, accompanied by significant improvements in sleep quality and reduced reliance on oral analgesics during the following 48 hours. Treatment acceptability was also substantially higher with TPVB, indicating a considerably more comfortable peri-procedural experience. Conclusion: TPVB combined with EMLA yielded profound improvements in procedural tolerability, early pain control, sleep quality, and patient acceptability during 8% capsaicin patch therapy for thoracic PHN, while markedly reducing opioid rescue needs. These findings support TPVB-assisted capsaicin therapy as a promising multimodal strategy deserving evaluation in prospective controlled trials.