Effectiveness of the 8% Capsaicin Patch in Localized Neuropathic Pain: A Quasi-Experimental Study.

Background: Neuropathic pain, characterized by injury or disease of the somatosensory nervous system, presents symptoms such as burning sensation, numbness, allodynia, and hyperalgesia, significantly impacting patients' quality of life. Common causes include diabetes, postherpetic neuralgia, post-surgical processes, amputation, and HIV. Pharmacological treatments, such as gabapentin, pregabalin, and tricyclic antidepressants, are first-line therapies. However, non-pharmacological therapies like the 8% capsaicin patch are gaining recognition for their efficacy and fewer side effects.

Objective: This study aims to analyse the management of the 8% capsaicin patch in patients with neuropathic pain by the nursing staff of the Chronic Pain Unit.

Method: A longitudinal quasi-experimental pre-post test study was conducted at the Chronic Pain Unit of the Virgen del Rocío University Hospital from June 2016 to December 2021. The study included patients over 18 years with localized neuropathic pain, indicated for an 8% capsaicin patch. Patients were evaluated using the Numerical Verbal Scale (NVS), EuroQol 5, and the MOS questionnaire at baseline, one month, and three months post-application. Statistical analyses were performed using SPSS® version 27.0.

Results: A total of 117 patients were enrolled, and 110 received treatment. The average age was 57.19 years, with 58.2% being female. Pain was primarily localized in the lower limb (63.6%), and post-surgical neuropathy was the most prevalent etiology (75.5%). Significant improvement in pain and health status was observed at one and three months post-application. Improvement in rest and sleep conditions was also noted, particularly at three months. The MCID was determined to be a reduction of 1.5 points in early assessments and 3 points in the final assessment.

Discussion: The study showed a clear trend toward pain improvement with the use of the 8% capsaicin patch. Results are consistent with previous studies, indicating significant pain reduction and improved quality of life. The findings suggest that repeated application of the patch may lead to sustained pain relief and further quality of life improvements. Adverse events were minimal and manageable.

Conclusion: The 8% capsaicin patch is effective in managing localized neuropathic pain, significantly improving pain, mobility, and quality of life. Nursing staff play a crucial role in the application and follow-up of this treatment, highlighting the importance of advanced training for optimal patient outcomes. Further research should focus on assessing the patch's synergistic capacity with pharmacological treatments and strategies to improve treatment adherence.