Drug Therapy for the Treatment of Chronic
Nonspecific Low Back Pain: Systematic Review
and Meta-analysis
Authors: Chung Joanne WY 
Published: March 2021

Background: Low back pain (LBP) is one of the most common health problems in adults. The
impact of LBP on the individual can cause loss of health status in the form of symptoms and loss
of function related to pain in the back; limitation of daily, leisure, and/or strenuous activities, and
disability. LBP also poses an economic burden to society, mainly in terms of one of the most common
reasons for seeking medical care (direct treatment costs), and accounts for the large number of work
days lost (indirect costs). To reduce the impact of LBP on adults, drug therapy is the most frequently
recommended intervention. Over the last decade, a substantial number of randomized clinical trials
of drug therapy for LBP have been published.
Objective: To determine the effectiveness of drug therapy for the treatment of chronic nonspecific
low back pain (CNLBP).
Study Design: Systematic review and meta-analysis
Methods: A systematic review and meta-analysis of randomized controlled trials was conducted.
Five databases (Medline, CINAHL, Science Direct, CAJ Full-text Database, and Cochrane databases)
were searched for articles published from 2002 to 2012. The eligibility criteria were randomized trials
and double-blind controlled trials of oral or injection drug therapy for CNLBP in subjects who were
aged at least 18 years old, published in English or Chinese. Two independent reviewers extracted
the data.
Results: A total of 25 drug therapy trials were included. cyclo-oxygenase-2 (COX-2) nonsteroidal
anti-inflammatory drugs (NSAIDs), tramadol, and opioids were commonly used. Only 5 trials studied
the efficacy of adjuvant analgesics of antiepileptics (n = 1) and antidepressants (n = 4) for CNLBP. The
standardized mean difference (SMD) for COX-2 NSAIDs in pain relief was -12.03 (95% confidence
interval [CI]: -15.00 to -9.06). The SMD for tramadol in pain relief was -1.72 (95% CI: -3.45 to 0.01).
As the 95% CI crossed 0, this effect size was not considered statistically significant. The SMD for the
overall effects of opioids in pain relief was -5.18 (95% CI: -8.30 to -2.05). The SMD for the partial
opioid agonist drug in pain relief was -7.46 (95% CI: -11.87 to -3.04).
Limitations: The follow-up periods of these included trials in the meta-analysis ranged from 4
to 24 weeks. The difference of follow-up periods influenced how study outcomes were recorded.
These included trials also had significant differences in patient selections. Some trials may actually
include CNLBP patients with neuropathic pain, as not having focal neurological findings or signs does
not mean that the pain is not neuropathic. Consequently, different pain conditions may influence
patients who responded to the same drug and then influence pooled estimates of treatment effect
size.
Conclusion: This review endorses the use of COX-2 NSAIDs as the first-line drugs for CNLBP.
Tramadol shows no statistically significant effect on pain relief, but has small effect sizes in improving
functioning. Among included opioid therapy studies, the overall effects of opioids and the partial
opioids agonist drug had statistically significant treatment effects in pain relief for CNLBP patients.
Key words: NSAIDs, opioids, antidepressants, drug therapy, low back pain, systematic review,
meta-analysis, randomized clinical trials