[Flupirtine in comparison with chlormezanone in chronic musculoskeletal back pain. Results of a multicenter randomized double-blind study].

Method: The analgesic and muscle-relaxing properties of flupirtine maleate, chlormezanone and placebo were compared in a total of 184 patients. Of these patients, 164 met the criteria of the treatment plan (intention to treat), and the data of 140 patients were finally evaluated in accordance with the test protocol. A positive response was defined as a reduction in pain intensity and muscle tension by 2 categories on the 5-category verbal scale "very severe/severe/moderate/mild/ none" on the seventh day of treatment.

Results: In the per-protocol-analysis the responder rate was 60.9% for flupirtine, 47.8% for chlormezanone, and 43.8% for placebo, the difference between drugs and placebo not being significant. The overall assessment of the physicians involved was very good/ good in 47.8% and satisfactory in 37.0% of the flupirtine group, very good/good in 45.6% and satisfactory in 17.4% of the chlormezanone group, the corresponding figures for the placebo group being 33.4% and 20.6%, respectively. Flupirtine was thus superior to placebo (p = 0.007). The incidence of adverse drug reactions was 14.8% (8/54) for flupirtine, 19.3% (11/57) for chlormezanone, and 7.3% (4/55) for placebo.