Abstract: Background: For symptomatic relief of low back pain, nonsteriodal anti-inflammatory drugs (NSAIDs) and analgesics are often in used in combination with muscle relaxants. However adverse effects, especially sedation, limit the use of some muscle relaxants. Thiocolchicoside (TCC) is a non-sedating muscle relaxant that has been shown to be safe and effective as monotherapy in the treatment of this problem. The present study was carried out to determine if the combination of thiocolchicoside and standard treatment is more effective than standard treatment alone.

Methods: Adults presenting with acute and subacute low back pain are recruited in 93 centers. Each center included four patients. Patients were randomised to receive either a NSAID or an analgesic for 5 to 7 days (referred to as "standard treatment") (Group 1) or "standard treatment" plus 8 mg of TCC (Muscoril) twice daily (Group 2) for 5 to 7 days. On inclusion and again on day 7, low back pain was evaluated with a visual analogue scale (VAS) and disability was evaluated with the Roland-Morris Disability Questionnaire. Pain and disability were evaluated again on day 31.

Results: 155 patients were analysed in Group 1 and 174 in Group 2. The vast majority (98.2%) of the patients received a NSAID as "standard treatment". The mean VAS and Disability Questionnaire scores of the two groups were equivalent at inclusion. At day 7, patients in both groups were improved but patients in Group 2 had significantly less pain (p=0.003) and disability (p=0.0005) than patients in Group 1, and this was also true at day 31. (p=0.004 and p =0.0005 respectively)

Conclusion: The addition of TCC to NSAID standard treatment resulted more effective for the symptomatic treatment of low back pain than the NSAID alone. In addition, the combination was well tolerated and produced no more adverse effects than the NSAID alone.