Topical capsaicin helps severe fibromyalgia pain; depletes pain-signaling substance P in local nerve endings

Article:
Short-term efficacy of topical capsaicin therapy in severely affected fibromyalgia patients
- Source: Rheumatology International, Jul 28, 2012

By Benigno Casanueva, et al.

[Note: capsaicin is the active component in chili peppers that causes a burning sensation where it touches tissues. It is thought to work by temporarily depleting or interfering with substance P in local nerve endings. Substance P is a protein involved in transmitting pain impulses to the brain, and its level in the cerebrospinal fluid of fibromyalgia patients is known to be 3 to 4 times normal. Many capsaicin-containing prescription and over-the-counter products for external application are available in a variety of forms and concentrations including 1% capsaicin (strong), and more-frequent 0.075%, generally for neuropathic pain, or 0.025%, generally for musculoskeletal pain. See MayoClinic.com for basic information about topical capsaicin.]

Article:
The purpose of this study was to evaluate the short-term efficacy of topical capsaicin treatment in patients severely affected by fibromyalgia.

One hundred and thirty fibromyalgia patients were randomly divided into two groups.

• The control group, 56 women and 4 men who continued their medical treatment,

• And the capsaicin group, 70 women who apart from continuing their medical treatment, also underwent topical capsaicin 0.075% 3 times daily for 6 weeks.

At the beginning of the program, there were no significant differences between the two groups in any of the analyzed parameters.

At the end of the treatment, there were significant improvements in the capsaicin group in the myalgic [pain] score (5.21 vs 3.8, p = 0.02) and global subjective improvement (22.8% vs 5%, p = 0.001). [Note: The myalgic score was determined by how much pressure could be applied to a tender point before the patient experienced pain, so a higher score indicates higher pain threshold.]

Six weeks after the end of the treatment, the experimental group showed significant differences in Visual Analogue Scale of depression (5.63 vs 7.35, p = 0.02), Fibromyalgia Impact Questionnaire (67.89 vs 77.7, p = 0.02), role limitations due to emotional problems (36.17 vs 17.2, p = 0.05), Fatigue Severity Scale (6.2 vs 6.6, p = 0.04), myalgic score (3.94 vs 2.66, p = 0.02) and pressure pain threshold (79.25 vs 56.71, p = 0.004).

In conclusion, patients severely affected by fibromyalgia can obtain short-term improvements following topical capsaicin 0.075% treatment three times daily for 6 weeks.

Source: Rheumatology International, Jul 28, 2012. DOI: 10.1007/s00296-012-2490-5, by Casanueva B, Rodero B, Quintial C, Llorca J, Gonzalez-Gay MA. Rheumatology Service, Specialist Clinic of Cantabria; Rodero Center, Neurophysiology Service, Santa Clotilde Hospital; Dept. of Epidemiology and Computational Biology, University of Cantabria; Rheumatology Service, Hospital Universitario Marques de Valdecilla, Santander, Cantabria, Spain. [Email: miguelaggay@hotmail.com]