Eperisone versus tizanidine for treatment of chronic low back pain.

Aim. Many therapies exist for treatment of chronic low-back pain (LBP) including the use of muscle relaxant and analgesic drugs. The aim of this paper was to compare efficacy and tolerability of eperisone and tizanidine in combination treatment with tramadol in chronic LBP. Methods. Sixty patients affected by chronic LBP associated with contractures of paravertebral muscles were randomized in two groups: Group E (30 patients) treated with eperisone; Group T (30 patients) treated with tizanidine. Both groups received tramadol retard 100 mg/day. VAS at rest and with effort were used at baseline (TO) and after 5 (T5), 10 (T10), 15 (T15) and 30 (T30) days of treatment. The Summed Pain Intensity Difference (SPID), the SPID percentage (SPID%) and the Total Pain Relief (TOTPAR), at rest (-r) and with effort (-e) were calculated. Results. In both groups a statistically significant reduction in VAS-r and VAS-e was observed during the treatment; similar reductions occurred in both groups at every timepoint. SPID-r and -e, SPID%-r and -e and TOTPAR-r and -e resulted similar between groups. A significant difference between groups occurred for incidence of somnolence: 16.6% for Group E versus 43.3% for Group T. Treatment was stopped due to adverse events in 5 patients of Group E and in 9 patients of Group T, without statistically significant difference. Conclusion. Both associations assumed for one month, have shown effective for LBP at rest and with effort. Eperisone/tramadol, reducing discontinuation and allowing a better adherence to the therapy, may be considered a viable option for the treatment of chronic LBP.