Background and ObjectiveLoxoprofen (LOX) is a nonsteroidal anti-inflammatory drug (NSAID). Although oral administration of LOX has been widely prescribed, clinical guidelines for osteoarthritis generally recommend topical rather than oral NSAIDs in specific patients. However, there is limited information on the effects of loxoprofen sodium oral (LOX-O) versus loxoprofensodium hydrogel transdermal patch (LOX-T) in myalgia patients. Hence, this non-inferiority study was designed to compare the efficacy and safety of LOX-O versus LOX-T in Chinese patients with myalgia.MethodsIn this double-blind, double-dummy, parallel-group, randomized controlled trial, 182 Chinese patients were enrolled and randomized equally to either LOX-T or LOX-O treatment for 2weeks. Patients in the LOX-T group applied one sheet of the active LOX-T once a day on the affected site and took one placebo tablet three times a day immediately after meals, whereas patients in the LOX-O group applied one sheet of the placebo patch once a day and took one active LOX-O three times a day. Primary endpoint was the proportion of patients with 50% overall improvement or higher at the final visit. The cutoff value of a non-inferiority difference was set as -10%.ResultsIn the full analysis set, the primary endpoint of final efficacy rate was 81.3% (n=91) in the LOX-T group and 72.2% (n=88) in the LOX-O group. The difference between the two groups was 9.1% [95% confidence interval (CI) -3.1 to 21.3%], which showed that LOX-T was non-inferior compared with LOX-O. No serious adverse events occurred in either group.ConclusionsThis trial showed the non-inferiority of LOX-T compared with LOX-O in efficacy and safety in Chinese patients with myalgia. Also, the characteristic features of topical LOX-T, such as better compliance and lower risk-benefit ratio, make it more favorable for clinical practice.Trial RegistrationThe study was registered in the isrctn.com registry (ISRCTN trial ID: ISRCTN16227145).