Evaluation of eperisone hydrochloride in the treatment of acute musculoskeletal spasm associated with low back pain: a randomized, double-blind, placebo-controlled trial

Eperisone hydrochloride is a centrally acting muscle relaxant inhibiting the pain reflex pathway, having a vasodilator effect. To evaluate the efficacy and tolerability of eperisone in patients with acute musculoskeletal spasm associated with low back pain. Prospective, randomized, double-blind, placebo-controlled, multicentric trial conducted at five tertiary care orthopedic centers across India. It was planned to enroll 240 patients of either sex between 18-60 years with acute musculoskeletal spasm (AMSP) with low back pain (LBP) due to spondylosis deformans, prolapsed disc or muscle sprain. Patients with other associated unrelated spasm conditions were excluded. Assessments were done for finger-to-floor distance (FFD), lumbar pain, Lasegue's sign, tenderness of vertebral muscles, need for rescue medication and response to therapy for efficacy and tolerability. Parametric data were analyzed by 't' test and ANOVA, and non-parametric data were analyzed using Mann-Whitney 'U' test and Kruskall-Wallis test. Proportions were compared using Fischer's (Chi-square) test. Two hundred and forty patients were randomized to receive eperisone 150 mg/day in three divided doses (n=120) or placebo (n=120) for 14 days, of which 15 patients did not complete and 225 patients completed the study (eperisone, 112 and placebo, 113). Significantly greater improvement in FFD (P