Diclofenac patch for topical treatment of acute impact injuries: a randomised, double blind, placebo controlled, multicentre study

Objectives: To investigate the clinical efficacy and safety of a newly developed diclofenac patch in the topical treatment of blunt impact injuries. Methods: This was a randomised, placebo controlled, double blind, multicentre study in 120 patients with traumatic blunt soft tissue injury. Within 3 h of the injury participants of sport competitions and training camps were enrolled and treated twice daily with the diclofenac or a placebo patch over a period of 7 days. Patients were randomised (1:1) to two parallel groups. Tenderness produced by pressure was measured twice daily during the first 3 days after enrolment as well as at day 7. Tenderness was defined as the amount of pressure (measured by a calibrated caliper at the centre of the injury) that first produced a pain reaction as reported by the patient. Results: The primary efficacy variable was the area under the curve for tenderness over the first 3 days. The diclofenac patch was significantly more effective than placebo (p<0.0001). The treatment effect was 64.7 kp h/cm2 (95% confidence interval 48.7 to 80.9) between diclofenac and placebo patches. These results were supported by all secondary efficacy variables. The diclofenac patch produced rapid pain relief as reflected by the time to reach resolution of pain at the injured site which was significantly shorter compared to placebo (p<0.0001). The diclofenac patch was well tolerated. The most frequently observed adverse events were local cutaneous adverse reactions (pruritus, rash) of minor severity occurring with the same frequency as in the placebo group. Conclusions: A newly developed diclofenac patch is effective and safe for the treatment of blunt impact injuries.