Citation:
Oikonomou I, Panagiotopoulou M, Christopoulos N, Loukeri E, Christodoulakis G, Kountis G, Papadakis SA, Chiotis I, Georgokostas A, Garantziotis N, et al. A Double-Blind Randomized Active-Controlled Trial Evaluating the Short-Term Efficacy of a Single Intramuscular Injection of a Fixed-Dose Combination Product Containing Diclofenac and Thiocolchicoside in Patients with Acute Moderate to Severe LowBack Pain. Journal of Clinical Medicine [Internet]. 2025;14.
Abstract:
Background/Objectives: Acute low back pain (LBP) is a prevalent cause of disabilityworldwide. If often involves both inflammation and reflex muscle spasm, suggesting
combined therapy with a non-steroidal anti-inflammatory drug (NSAID) and a muscle
relaxant may provide superior relief. This study aimed to evaluate the short-term efficacy and safety of a single intramuscular (IM) injection of a fixed-dose combination (FDC) product containing Diclofenac and Thiocolchicoside versus Diclofenac monotherapy in adults with acute LBP. Methods: We conducted a phase III multicenter, randomized, double-blind, parallel-group trial in 140 patients with acute LBP of moderate to severe intensity. Patients were allocated 1:1 to receive either the combination of Diclofenac sodium 75 mg + Thiocolchicoside 4 mg (FDC product, Test Group) or Diclofenac sodium 75 mg alone (Diclofenac monotherapy, Reference Group) via a single IM injection. The primary
outcome was the change in patient-reported pain intensity using the Visual Analogue Scale
(VAS) from baseline to 3 h post-dose. Key secondary outcomes included pain change at
1 h in the VAS, improvement in lumbar mobility (finger-to-floor distance test, FTF), the
proportion of patients achieving >30% pain reduction, and the incidence of adverse events
(AEs). Randomization was centralized and both investigators and patients were blinded
to the treatment. Results: All 140 randomized patients completed the trial. At 3 h postinjection,
the combination therapy produced a significantly greater mean pain reduction
than monotherapy (41.52 mm vs. 28.13 mm on the 100 mm VAS; p < 0.0001). Superiority of the combination was already evident at 1 h post-dose (VAS reduction 27.61 mm vs. 20.40 mm; p = 0.0089). Lumbar flexion improved more with the combination at 3 h (mean FTF distance improvement 14.52 cm vs. 7.94 cm; p < 0.0001) and at 1 h (9.21 cm vs. 4.62 cm;