Background: Muscle relaxants are widely used to treat low back pain (LBP), one of the most frequent health problems in industrialized countries. For this indication, the European Medicines Agency (EMA) recently had imposed restrictions for some muscle relaxants, anti-inflammatories and analgesics; Tetrazepam even had to be withdrawn from the market. Therefore methocarbamol remains the only approved muscle relaxant. Methocarbamol is well-established for the treatment of LBP associated with myofascial components, although more recent clinical studies have not been published. Therefore this publication summarizes and revaluates post-hoc data of an efficiency study of methocarbamol, that was performed in 2002, but had not been published yet.
Method: This was a randomized, placebo controlled multi-centre study. Inclusion criteria were acute low back pain for at least 24 h associated with spasms in the pelvic/lumbar region and restriction of mobility. Patients were randomly assigned to a group treated with orally administered Ortoton® (n = 98) or placebo (n = 104). Drugs were administered for up to 8 days, but treatment of individual patients was discontinued as soon as a pain-free state was achieved. Individual pain perception was quantified by means of a visual analog scale (VAS). The fingertip-to-floor distance was measured as an indicator of lumbar flexion. Mobility restrictions were also assessed by a modified Schober's test. In addition, a questionnaire was used by patients and physicians to rate the efficacy of treatment.
Results: In the methocarbamol group 44% of the patients pre-terminated due to complete pain relief (placebo: 18%) and 19% discontinued because the treatment was considered ineffective (placebo 52%, p < 0,0001). Measures of mobility (fingertip-to-floor distance, Schober's test) and improvement of mobility as perceived by physician and patient at the individual end of study all were clearly in favor of the patients treated with methocarbamol. At the final visit, 67% of the patients who had received Ortoton® (35% of placebo patients) and 70% of their physicians (control group: 36%) considered the treatment to be effective. No severe adverse effects were observed during the study (7 symptoms in 5 patients).
Conclusion: This study showed that methocarbamol, orally administered, is an efficient and well-tolerated therapeutic option for patients suffering from acute LBP and the typically associated restrictions of mobility.