Analgesics do not improve function in patients with low back pain


A randomised-controlled trial, published ahead-of-print in the European Spine Journal, has found that acetaminophen [paracetamol]/tramadol is not associated with significant improvements in function compared with placebo in patients with chronic low back pain. However, patients who do respond to this combination of analgesics have significant improvements in function compared with those who do not respond—indicating that analgesic may be effective for functional improvement in a subset of patients with low back pain. 

Study authors Henrica Schiphorst Preuper (Department of Rehabilitative Medicine, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands) and others write that guidelines recommend that analgesics should be prescribed “time contingent (under four weeks), stepwsie from light to strong” for patients with non-specific low back pain. However they add that although analgesics are known to reduce pain and self-reported disability in patients with chronic low back pain, the effect of oral analgesics on functional capacity has not been prospectively studied.

Schiphorst Preuper et al write: “The objective of this study was to investigate the effect of the combination of acetaminophen/tramadol on functional capacity and self-reported disability and secondarily on pain relief in patients with chronic low back pain.”

In the study, patients with non-specific chronic low back pain of more than three months’ duration who were on a waiting list for rehabilitative treatment were randomised to acetaminophen/tramadol (25) or placebo (25). Functional capacity, the authors report, was measured by reviewing the patients’ ability to lift, carry, and perform static bending and dynamic bending. Furthermore, the Roland Morris Disability Questionnaire (RMDQ) was used to assess self-reported disability.

Schiphorst Preuper et al found that there were no significant differences in improvements in functional capacity (before and after treatment) between the group receiving acetaminophen/tramadol and those receiving placebo. However, they comment that patients who responded to treatment in the acetaminophen/tramadol group tended to improve on lifting performance (p=0.10) and had a significant reduction in the RMDQ (p=0.02) compared with non-responders in that group. They add: “Characteristics of responders showed a significantly lower score on subscale catastrophising of the pain cognition list (median 35.5 vs. 44 in non-responders; p=0.005)”, explaining that this may have been a “mediator of treatment outcome”.

Schiphorst Preuper et al conclude: “Pharmacotherapy for pain could be considered as one of the options in an overall management plan. It is important, however, to identify the subgroup of patients who might benefit from pharmacotherapy. Future research should include large study samples, longer treatment duration, and also patients with a shorter history of complaints.”