Diclofenac patch for the treatment of acute pain caused by soft tissue injuries of limbs: a randomized, placebo-controlled clinical trial

BACKGROUND: This study aimed to assess the efficacy and the safety of a newly-developed patch containing diclofenac sodium 140 mg in patients affected by acute soft tissue sport injuries, such as contusion, strain and sprain with a randomised, double-blind, placebo-controlled trial.

METHODS: One hundred and sixty-four subjects were recruited within 3 hours of a soft-tissue sport injury and were equally assigned to receive diclofenac or placebo patch applied twice a day for 7 days. The primary study endpoint was reduction in severity of pain on movement from baseline to 48 hours measured by Visual Analogue Scale. Secondary outcomes were reduction of pain on movement and at rest, reduction of pain on pressure, time to efficacy onset, global efficacy assessment and use of rescue analgesics.

RESULTS: The reduction of pain on movement from baseline to day 2 was markedly greater in the diclofenac group compared with placebo (treatment effect: -24.25 mm, P<0.001 between groups). Statistically significant improvements were also observed in the diclofenac group compared to placebo for the secondary variables of pain on movement and at rest, pain on pressure, time to efficacy onset and global patient and investigator efficacy assessment. Local adverse reactions at the application site were reported in comparable rates in the two groups.

CONCLUSIONS: The diclofenac patch could be a safe and effective alternative to the oral administration of non-steroidal anti-inflammatory drugs in the treatment of minor sport injuries.