Acute Effect of Topical Menthol on Chronic Pain in Slaughterhouse Workers with Carpal Tunnel Syndrome: Triple-Blind, Randomized Placebo-Controlled Trial

Abstract

Topical menthol gels are classified “topical analgesics” and are claimed to relieve minor aches and pains of the musculoskeletal system. In this study we investigate the acute effect of topical menthol on carpal tunnel syndrome (CTS). We screened 645 slaughterhouse workers and recruited 10 participants with CTS and chronic pain of the arm/hand who were randomly distributed into two groups to receive topical menthol (Biofreeze) or placebo (gel with a menthol scent) during the working day and 48 hours later the other treatment (crossover design). Participants rated arm/hand pain intensity during the last hour of work (scale 0–10) immediately before 1, 2, and 3 hours after application. Furthermore, global rating of change (GROC) in arm/hand pain was assessed 3 hours after application. Compared with placebo, pain intensity and GROC improved more following application of topical menthol (P = 0.026 and P = 0.044, resp.). Pain intensity of the arm/hand decreased by −1.2 (CI 95%: −1.7 to −0.6) following topical menthol compared with placebo, corresponding to a moderate effect size of 0.63. In conclusion, topical menthol acutely reduces pain intensity during the working day in slaughterhouse workers with CTS and should be considered as an effective nonsystemic alternative to regular analgesics in the workplace management of chronic and neuropathic pain.

Topical menthol increases cutaneous blood flow

“…The ability of topically applied menthol to attenuate pain is well established (Airaksinen et al, 2004; Hill and Sumida, 2002; Sundstrup et al, 2014). These data do not refute using topical menthol gels as analgesics for muscle and joint pain.…”

The Clinical Effectiveness of Biofreeze® Topical Analgesic on Musculoskeletal Pain: A Systematic Review

“…Change in VAS pain scores with Biofreeze in various musculoskeletal conditions in relation to clinically important differences. Based on data from Bishop et al, 13 Zhang et al, 18 Topp et al, 21 and Sundstrup et al 23 Page and Alexander. J Perform Health Res.…”

“…Sundstrup et al 23 compared the effects of Biofreeze gel and a placebo gel on 10 slaughterhouse workers with symptoms of carpal tunnel syndrome. In their triple-blinded experiment, the researchers measured VAS at 1, 2, and 3 hours after application, separated by 48 hours.…”

Pain Management with Non-pharmacological Methods in Patients Undergoing Coronary Artery Bypass Graft Surgery: Review

“…Ancak, Sundstrup ve ark.nın karpal tünel sendromlu hastalarda mentol etkinliğini değerlendiren çalışmasında, hastaların topikal mentol uygulamasında ağrı yoğunluklarının azaldığı gözlenmiştir. 19 …”