Considerable uncertainty exists about the clin- ical efficacy and safety of muscle relaxants for the treatment of low back pain, according to the results of a systematic review and meta-analysis published in The BMJ. Investigators conducted a literature review to assess the efficacy, acceptabil- ity, and safety of muscle relaxants for low back pain. Based on a meta-analysis of data from 31 of 49 identified studies (6,505 participants), the re- searchers found that for acute low back pain, very low-certainty evidence showed that at 2 weeks or less, non-benzodiazepine antispasmodics were as- sociated with a reduction in pain intensity versus control (mean difference −7.7, 95% CI, −12.1 to −3.3) but not a reduction in disability (−3.3; 95% CI, −7.3 to 0.7). Compared with control for acute low back pain, low- and very low-certainty evidence showed that non-benzodiazepine anti- spasmodics might increase the risk for an adverse event (relative risk, 1.6; 95% CI, 1.2 to 2.0) but might have little to no effect on acceptability (rel- ative risk, 0.8; 95% CI, 0.6 to 1.1). “Large, high- quality, placebo-controlled trials are urgently needed to resolve uncertainties about the efficacy and safety of muscle relaxants for low back pain,” the authors wrote.