Back and neck pain are common musculoskeletal disorders. Topical non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used to reduce pain and inflammation with fewer systemic side effects and drug interactions compared with oral NSAIDs. This study assessed efficacy and tolerability of a topical combination of capsaicin + diclofenac to treat acute back/neck pain.
In a randomized, double-blind, controlled, multicenter, parallel group trial, 746 patients were treated twice-daily for 5 days with diclofenac 2% + capsaicin 0.075%, diclofenac 2%, capsaicin 0.075% or placebo. Efficacy assessments included change and area under the curve in pain on movement for the worst procedure (POM WP), change in pressure algometry, and number of patients with decrease in POM WP of ≥ 30% and ≥ 50%. Adverse events (AEs) were recorded.
Change in POM WP between baseline and day 2 evening, 1 h after drug application, demonstrates superiority of the combination (− 3.05 cm) versus diclofenac alone (− 2.33 cm) and placebo (− 2.45 cm), but not capsaicin alone (− 3.26 cm). AEs were consistent with known safety profiles.