Analgesic efficacy of a lecithin-vehiculated diclofenac epolamine gel in shoulder periarthritis and lateral epicondylitis: a placebo-controlled, multicenter, randomized, double-blind clinical trial

Abstract

Diclofenac epolamine (2-hydroxyethyl-pyrrolidine) (DHEP) is a diclofenac salt endowed with enhanced cutaneous permeation. To optimize its absorption after topical application, a lecithin-enriched DHEP 1.3% gel has been developed (DHEP lecithin gel) and investigated in patients with shoulder periarthritis and lateral epicondylitis in a placebo-controlled, multicenter double-blind clinical trial. One hundred fifty-eight patients were randomized to a 10-day treatment with DHEP lecithin gel or placebo (5 g t.i.d. applied on the painful area). The efficacy criteria were pain measured by visual analog scale (VAS) while performing a specific standardized movement, intake of rescue medication (paracetamol), and the disabilities of the arm, shoulder and hand (DASH) questionnaire. VAS scores indicated a consistently higher analgesic activity of DHEP lecithin gel. At day 3, pain was reduced by -20.1 +/- 20.2 and -9.9 +/- 12.7 mm in the DHEP lecithin gel- and placebo-treated patients, respectively (p < 0.001); at day 6 of treatment, DHEP lecithin gel induced a pain reduction of -33.2 +/- 26.1 mm, while the reduction achieved with placebo was only -21.2 +/- 18.8 mm (p < 0.001). The mean changes in DASH questionnaire indicated that DHEP lecithin gel was more effective than placebo in improving patient well-being and reducing difficulties in performing the activities most severely impaired by rheumatism, while no difference was observed between the two treatments in consumption of rescue medication. In conclusion, these results indicate that DHEP lecithin gel is a topically effective analgesic product in patients with shoulder periarthritis or lateral epicondylitis and provide further evidence on the use of topical nonsteroidal anti-inflammatory drugs as an optimal approach to the treatment of localized musculoskeletal disorders.