Efficacy and safety of eperisone in patients with low back pain: a double blind randomized study.

Eperisone hydrochloride (4'-ethyl-2-methyl-3-piperidinopropiophenone hydrochloride) is an antispastic agent used for treatment of diseases characterized by muscle stiffness and pain. The aim of this research was to investigate the efficacy of eperisone in patients with acute low back pain and spasticity of spinal muscles. The study design was a randomized, double-blind (double-dummy) study in 160 patients with low back pain and no Rx finding of major spinal diseases, randomly assigned to a treatment with oral eperisone 100 mg three times daily (t.i.d.) or thiocolchicoside 8 mg twice daily (b.i.d.) for 12 consecutive days. Analgesic activity was evaluated by scoring "spontaneous pain" (VAS) and pain on movement and pression (4-digit scale), while muscle relaxant activity of the medication was evaluated by means of the "hand-to-floor" distance and the Lasegue's manoeuvre. All the measures were done at the inclusion day and after 3, 7 and 12 days of treatment. The two medications had comparable analgesic and muscle relaxant efficacy. Sponta-neous pain and pain on movement/pressure were significantly reduced by both treatments. Moreover, both eperisone- and thiocolchicoside-treated patients showed a clinically evident muscle relaxation as proved by a progressive reduction in the "hand-to-floor" distance and increase in the articular excursion (Lasegue's manoeuvre). Only 5% of eperisone-treated patients showed minor gastrointestinal side effects, while the incidence of side effects in the thiocolchicoside group was 21.25%. Moreover, in the thiocolchicoside-treated patients also diarrhoea was present, which reached a moderate intensity in some cases. In conclusions, eperisone represents a valuable and safer alternative to other muscle relaxant agents for treatment of low back pain.