Efficacy and Safety of the Combination of Diclofenac and Thiocolchicoside in the Treatment of Low Back Pain and Other Conditions: Systematic Review of the Literature

Background/Objectives: Low back pain (LBP) is a leading cause of disability worldwide. Diclofenac, a non-steroidal anti-inflammatory drug (NSAID), and thiocolchicoside, a muscle relaxant, are commonly combined to target inflammation and muscle spasm. However, the efficacy and safety of their combination remain under discussion. This systematic review evaluates the efficacy and safety of diclofenac-thiocolchicoside therapy for LBP and other musculoskeletal conditions. Methods: A systematic review was conducted following PRISMA guidelines. Eligible studies included randomized controlled trials (RCTs) and observational studies comparing diclofenac-thiocolchicoside combination with placebo, monotherapy, or alternative treatments. A search was performed in PubMed, Scopus, and relevant websites, identifying articles published up to 30 September 2024. Studies from trial registries were excluded. Risk of bias was assessed using Revised Cochrane Risk of Bias for randomized trials (RoB 2) for RCTs and the Newcastle-Ottawa Scale (NOS) for observational studies. Evidence certainty was evaluated with the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework. Results were visualized using Robvis, tables, and graphs. Results: Of 393 identified records, 9 studies (1097 patients) met the inclusion criteria. Seven RCTs reported significant pain reduction and functional improvement with combination therapy compared to placebo or active controls. However, study heterogeneity, dosage variations, and risk of bias limited comparability. Adverse events (AEs) included gastrointestinal (GI) discomfort and drowsiness, though no severe complications were consistently reported. Conclusions: Despite methodological limitations, the diclofenac-thiocolchicoside combination demonstrates promising efficacy for acute LBP and musculoskeletal pain management. However, there is no clear evidence of its clinical superiority over other available treatments, due to study heterogeneity and potential biases. Rigorous, standardized research with larger sample sizes and consistent methodologies is essential to definitively establish the efficacy and safety of diclofenac-thiocolchicoside, providing clearer guidance for clinical decision-making.