Diclofenac epolamine medicated plaster in the treatment of minor soft tissue injuries: a multicenter randomized controlled trial

Abstract

Objective:To investigate the efficacy and safety of a topical plaster containing diclofenac epolamine (DHEP) 1.3% in the treatment of patients with acute minor soft tissue injuries in China.Research design and methods:This prospective, randomized, double blind, placebo-controlled study had balanced random assignment to DHEP medicated plaster and placebo plaster. A total of 384 patients, aged 18–74 years, with minor soft tissue injury occurring within 72 hours of study entry were enrolled and randomized. Plasters were applied twice daily for seven consecutive days. Outcomes were assessed in three visits over 7 days, in addition to patients’ daily self-assessment and an adverse events follow-up visit on day 21.Main outcome measures:The primary efficacy endpoint was the mean change from baseline in pain on movement on a 100 mm Visual Analogue Scale (VAS) after 7 days of treatment. Secondary efficacy endpoints included pain on movement day-by-day evaluation, summed pain intensity difference, overall treatment efficacy, rescue medication consumption, and treatment tolerability.Results:Reduction in pain on movement after 7 days of treatment, the primary efficacy endpoint, was statistically significantly greater in the DHEP plaster group than with placebo (reduction in VAS pain scores −53.78 ± 16.96 vs −37.02 ± 18.30 for DHEP vs placebo, p < 0.0001). The greater analgesic effect of DHEP plaster was evident by day 1 and increased progressively throughout the treatment period. Global pain relief and overall treatment efficacy were significantly better with DHEP. Both DHEP and placebo plaster were well tolerated with few adverse events, mostly application site reactions.Conclusions:A medicated plaster containing DHEP applied to the affected site in Chinese patients with minor soft tissue injury, such as sprains, strains and contusions, was significantly more effective than placebo at reducing pain scores. Onset of action was rapid and the DHEP plaster was safe and well tolerated. The main limitation was the use of a subjective, though validated, self-reported VAS to assess the primary endpoint.