Background & Aims

Capsaicin is a compound extracted from spicy chili peppers. It is used in the form of patches at concentrations of 8% in applications lasting 30 to 60 minutes in patients with peripheral neuropathic pain (Allodynia), desensitizing nociceptor fibers through the TRPV1 receptor (Transient Receptor Potential Vanilloid type 1), which is an ion channel sensitive to heat, acidic pH, and vanilloids such as capsaicin. This phenomenon enables the reduction of pain intensity and/or area. It was incorporated for treating neuropathic pain in Chile in late 2022 and has been available in the Hospital del Trabajador since early 2023.
This first case series aims to characterize the intervened population between April 2023 and April 2024 in Hospital del Trabajador and describe the response to patch application according to the sessions administered, both in terms of perceived improvement, reduction in intensity and area of allodynia, and the immediate and late reported adverse effects.

Methods

This single-center case series study recorded cases from patients over 18 years old with peripheral neuropathic pain who were part of the first 8% capsaicin patch treatment group in the Rehabilitation Department of the Hospital del Trabajador Santiago between April 2023 and April 2024. People with adverse skin conditions for topical agents and known allergies to peppers or other patch compounds were excluded from the original treatment protocol. Before treatment, sociodemographic, laboral, and clinical data were collected from medical charts. At the last medical appointment, pain intensity, allodynia area, number of patch applications, and treatment perception were recorded from clinical records. Immediate adverse effects were obtained from the application record and the late adverse effect from the last medical appointment.

Results

85 cases filled the inclusion criteria. Mean age was 48,8 years SD 11.6 y., and 65% (56) were women. Comorbidities were present in 49.4%, where only 4 patients had Diabetes Mellitus. Neuropathic pain was categorized based on recorded etiologies. The majority of cases stem from surgical wounds (48.2%), direct trauma (21.2%), Complex Regional Pain Syndrome (CRPS) (20%), and amputation-related allodynia (10.6%). The most common location for the injuries was the lower limb (65.8%). 8 patients were lost to follow-up and were not considered for the response frequencies. The best response percentage was seen in patients without CRPS, with 65.07% favorable response. Patients with 1 session (43) showed a 55.8% (23) favorable response; those with 2 sessions (17) had a 64.7% (11); those with 3 sessions (16) had an 81.25% (13). Immediate adverse effects included burning in 55 (64.7%), itching in 48 (56.5%), and pain in 3 (3.52%), while 15 patients (17.64%) reported no discomfort. Late adverse effects were described in just 2 patients (headaches and vomiting).

Conclusions

The use of 8% capsaicin patches at Hospital del Trabajador tend to show promising results in managing peripheral neuropathic pain. Increased favorable responses was observed in patients receiving multiple sessions. Patients with direct trauma seems to have a better response rate compared to those with CRPS. Side effects were generally mild, with no reported severe reactions. These findings do not establish safety and effectiveness; further studies are required to confirm these aspects in our population.

References

Hecke, O., Austin, S., Khan, R., Smith, B., & Torrance, N. (2014). Neuropathic pain in the general population: A systematic review of epidemiological studies. PAIN®, 155, 654-662. https://doi.org/10.1016/j.pain.2013.11.013.

Durán, Josefinaa; Tejos-Bravo, Macarenab,c; Cid, Vicented; Ferreccio, Catterinad; Calvo, Margaritab,c,e,*. Chronic pain in Chile: first prevalence report of noncancer chronic pain, fibromyalgia, and neuropathic pain and its associated factors. PAIN 164(8):p 1852-1859, August 2023. | DOI: 10.1097/j.pain.0000000000002886

Anand, P., & Bley, K. (2011). Topical capsaicin for pain management: therapeutic potential and mechanisms of action of the new high-concentration capsaicin 8% patch. BJA: British Journal of Anaesthesia, 107, 490 – 502. https://doi.org/10.1093/bja/aer260.

Mandadi, S., Numazaki, M., Tominaga, M., Bhat, M., Armati, P., & Roufogalis, B. (2004). Activation of protein kinase C reverses capsaicin-induced calcium-dependent desensitization of TRPV1 ion channels.. Cell calcium, 35 5, 471-8 . https://doi.org/10.1016/J.CECA.2003.11.003.

Mankowski, C., Poole, C., Ernault, É., Thomas, R., Berni, E., Currie, C., Treadwell, C., Calvo, J., Plastira, C., Zafeiropoulou, E., & Odeyemi, I. (2017). Effectiveness of the capsaicin 8% patch in the management of peripheral neuropathic pain in European clinical practice: the ASCEND study. BMC Neurology, 17. https://doi.org/10.1186/s12883-017-0836-z.

Simpson, D., Robinson-Papp, J., Van, J., Stoker, M., Jacobs, H., Snijder, R., Schregardus, D., Long, S., Lambourg, B., & Katz, N. (2017). Capsaicin 8% Patch in Painful Diabetic Peripheral Neuropathy: A Randomized, Double-Blind, Placebo-Controlled Study.. The journal of pain : official journal of the American Pain Society, 18 1, 42-53 . https://doi.org/10.1016/j.jpain.2016.09.008

Presenting Author

Tania Durán

Poster Authors

Iñaki Bizama

MD

Hospital del Trabajador

Lead Author

E-mail

Sebastián Muñoz

MD

Hospital del Trabajador

Lead Author

E-mail

Tania Durán

MD

Hospital del Trabajador

Lead Author

E-mail

Javier Navarro

MD

Hospital del Trabajador

Lead Author

E-mail

Consuelo Ravanal

MD

Hospital del Trabajador

Lead Author

E-mail

Javiera Cortés

Hospital del Trabajador

Lead Author

E-mail

Topics

  • Specific Pain Conditions/Pain in Specific Populations: Neuropathic Pain - Peripheral

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