The present study aimed to compare the efficacy and safety of loxoprofen sodium cataplasm (LSC) with those of flurbiprofen cataplasm (FPC) in osteoarthritis (OA) treatment. In this multicenter, randomized controlled trial, subjects meeting the inclusion and exclusion criteria were randomly assigned to the two treatment groups. According to the manufacturer's instructions, the first group received LSC once daily, with the application of one patch per area for 2 weeks, whereas the second group received FPC twice daily, with the application of one patch per area for 2 weeks. The treatment response was evaluated based on the Visual Analog Scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) global score, Lysholm score and adverse events for 296 patients enrolled across three subcenters, with 192 patients in the LSC group and 104 patients in the FPC group. The treatment effectiveness rates, based on the VAS, WOMAC global and Lysholm scores, were 74.46, 61.41 and 85.25%, respectively, for the LSC group and 43.14, 31.37 and 66.67%, respectively, for the FPC group. Regardless of the effectiveness criterion used, the LSC group exhibited a superior treatment effectiveness rate compared with the FPC group. After 2 weeks of treatment, OA symptoms improved in both groups, with the LSC group exhibiting lower VAS (P<
0.05) and WOMAC global scores (comprising pain, stiffness and physical function scores) compared with the FPC group (P<
0.05), while the Lysholm score was higher in the LSC group compared with the FPC group (P<
0.05). The FPC group experienced more general adverse events (P>
0.05) and dressing shedding (P<
0.05) compared with the LSC group, whereas the LSC group had more specific adverse events (such as skin itching, fever and allergy) compared with the FPC group (P>
0.05). The results suggested that compared with FPC, LSC exhibited higher short-term efficacy and a consistent safety profile. The present study was registered at Chinese Clinical Trial Register (chictr.org.cn
ChiCTR2300072504
date of registration, June 15, 2023).