Efficacy and Safety of Pregabalin for Restless Legs Syndrome in Korean Adults: A Randomized, Double-Blind, Placebo-Controlled Trial.

Background and purpose: To evaluate the clinical efficacy and safety of pregabalin in Korean adults with restless legs syndrome (RLS).

Methods: In this randomized, multicenter, double-blind, placebo-controlled trial, 78 patients with RLS with an International Restless Legs Scale (IRLS) score ≥15 were randomized 1:1 to receive either pregabalin (n=39) or placebo (n=39) for 12 weeks. The primary efficacy outcome was the change in the IRLS score, and the secondary outcomes included the Clinical Global Impression-Improvement scale and changes in scores on other RLS symptom questionnaires. Safety was assessed by monitoring treatment-emergent adverse events (TEAE). This study was registered at ClinicalTrials.gov (NCT04161027).

Results: At baseline, the mean IRLS scores were 23.2±5.8 in the pregabalin and 24.5±5.2 in the placebo group (p=0.297). After 12 weeks, the baseline-adjusted change in the IRLS score was -6.8 (95% confidence interval [CI] -9.3 to -4.3) in the pregabalin group and -5.4 (95% CI -7.9 to -2.8) in the placebo group, with no significant difference between the groups (p=0.420). The secondary efficacy outcomes did not differ between the two groups. The incidence of TEAE was similar between the two groups (48.7% vs. 51.3%, p=0.821), with dizziness being the most common TEAE.

Conclusions: This study failed to demonstrate the therapeutic effect of pregabalin compared with placebo for RLS in Korean adults. Possible reasons for the negative results include low dose, insufficient sample size, and substantial placebo response. Further investigations are warranted to optimize pregabalin therapy in Korean adults with RLS.