A multi-center, double-blind, randomized parallel-group Phase IV study comparing the efficacy and safety of thiocolchicoside ointment versus placebo in patients with chronic mechanical low back pain and an acute muscle spasm

Abstract

Objectives: This study aims to evaluate the efficacy and safety of thiocolchicoside (TCC) ointment treatment compared to placebo in patients with chronic mechanical low back pain (LBP) accompanied by acute muscle spasms. Patients and methods: A total of 292 adult patients (106 males, 186 females; mean age: 38.5±11.2 years; range, 18 to 64 years) were randomized to TCC group (n=147) and placebo group (n=145) in 12 centers between March 2020 and March 2021. Eight patients from each group were excluded from the analysis. The primary endpoint was pressure pain threshold (PPT) on Day 3, which was measured using a pressure algometer. Secondary endpoints were PPT on Day 7, patient, and physician Visual Analog Scales-pain (VAS-pain) on Days 3 and 7, and safety. Results: The PPT values on Day 3 was not significantly different between the treatment groups (p=0.701). Similarly, TCC and placebo group had similar VAS-pain scores over trial period (p=0.577 or higher for comparisons). Significantly higher PPT values and lower VAS-pain scores on Days 3 and 7 were observed in both groups (p<0.001 for all). In patients with a PPT value of ≥3.87, TCC arm had higher PPT on Day 3 compared to placebo (p=0.029). Three patients (two in the TCC arm and one in the placebo arm) discontinued the trial due to an adverse event. Conclusion: Topical TCC can be an appropriate option in a subset of patients with mild chronic LBP accompanied by muscle spasms. In a subset of patients with milder pain intensity, topical TCC may improve pain earlier. The results of this trial are compatible with the treatment approaches used in daily practice.