A Multicentre, Randomised, Double- Blind Study Comparing the Efficacy and Tolerability of Intramuscular Dexketoprofen versus Diclofenac in the Symptomatic Treatment of Acute Low Back Pain

Methods: A randomised, double-blind, parallel, active controlled, multicentre study that included 370 outpatients with acute low back pain was conducted to compare the analgesic efficacy of dexketoprofen 50mg twice daily versus diclofenac 75mg twice daily administered intramuscularly for 2 days. Efficacy outcomes were assessment of pain intensity (PI) measured on a visual analogue scale, total PI scores from baseline to 6 hours after the first-dose administration (primary efficacy endpoint; SAPID_0-6), score on a physical disability scale using the Roland Disability Questionnaire (RDQ), and use of rescue medication. Tolerability and safety were also assessed as secondary variables.

Results: The adjusted mean (SAPID_0-6) scores were very similar, 117.3 mm/h with dexketoprofen and 114.7 mm/h with diclofenac. The adjusted ratio of means was 1.023 and the lower 95% confidence limit was 0.81, demonstrating noninferiority of dexketoprofen (defined by a lower limit of the 95% CI >0.80) in comparison with diclofenac (per-protocol analysis). The median change in the RDQ was -6 points for both groups (p = 0.69), showing an overall improvement on the disability scale. No significant differences between groups were observed regarding the percentage of patients needing rescue medication or in the mean values of pain after repeated doses (SAPID_0-last). Dexketoprofen was well tolerated, with a reported incidence of adverse events similar to that of diclofenac. No serious adverse events were reported in either treatment group.