Efficacy of epicutaneous Diractin® (ketoprofen in Transfersome® gel) for the treatment of pain related to eccentric muscle contractions

OBJECTIVE To investigate the effect of epicutaneously applied Diractin (ketoprofen in Transfersome gel) on pain induced by eccentric muscle contractions. METHODS Three pilot studies which were subsequently pooled for a meta-analysis compared the efficacy of a single application of 25 mg ketoprofen in Diractin to 25 mg oral ketoprofen and placebo for the treatment of pain induced by 50 eccentric contractions of the elbow flexor muscles. In addition, the effect of multiple usage of up to 100 mg ketoprofen in Diractin bid over seven days on pain induced by walking down stairs with a total altitude of 200 meters was investigated. RESULTS A single dose of 25 mg ketoprofen in Diractin after the elbow flexion exercise was significantly superior to placebo from 5 to 12 hours after treatment and also to oral ketoprofen at some time points after treatment. In contrast, oral ketoprofen was not different to placebo at any time after treatment. Multiple doses of up to 100 mg ketoprofen Diractin provided significant more pain relief than placebo on muscle pain induced by walking down stairs. CONCLUSIONS Eccentric exercise-induced muscle soreness was shown to be an appropriate acute pain model to evaluate the efficacy of nonsteroidal anti-inflammatory drugs applied epicutaneously with Transfersome carriers. Diractin proved to be efficacious in relieving pain from eccentric muscle contractions and muscle over-exercise, respectively. The effect needs to be confirmed in a larger prospective clinical trial.