EVIDENCE-BASED ANSWER:
Short-term (<4 months) treatment with opioids provides modest relief of chronic low back pain, but only minimal improvement in function compared with placebo (strength of recommendation [SOR]: B, systematic review of lower-quality randomized controlled trials [RCTs]).
Tramadol isn’t superior to nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief (SOR: A, consistent results from RCTs). In addition, oxycodone with titrated morphine isn’t better than naproxen for relieving pain or improving function (SOR: C, a low-quality RCT).
Although no long-term RCTs have been done, cohort studies have shown that 6 to 12 months of opioid use is associated with a small decrease in pain and either very minimal improvement in, or worsening of, disability (SOR: B, prospective cohort trials).
EVIDENCE SUMMARY
A systematic review and meta-analysis of 15 RCTs with a total enrollment of 5540 assessed the efficacy of opioids in adults with chronic low back pain of at least 12 weeks’ duration.1 Five low-quality studies (1378 patients) that compared tramadol with placebo found tramadol to be moderately superior to placebo for relieving pain (standard mean difference [SMD]= -0.55; 95% confidence interval [CI], -0.66 to -0.44) but only modestly better for improving function (SMD= −0.18; 95% CI, -0.29 to -0.07).
Six trials with 1887 patients compared strong opioids (morphine, hydromorphone, oxycodone, oxymorphone, and tapentadol) with placebo. The opioids were better than placebo for improving pain (SMD= -0.43; 95% CI, -0.52 to -0.33) and function (SMD= -0.26; 95% CI, -0.37 to -0.15). The general interpretation of SMD effect size is 0.2=small, 0.5=medium, 0.8=large. In this case, larger negative numbers correlate with greater improvement.
How opioids stack up against NSAIDs
Two separate double-blind, double-dummy studies randomized adults with low back pain of at least 12 weeks’ duration to receive celecoxib 200 mg twice daily (404 and 398 patients, respectively) or tramadol 50 mg 4 times daily (392 and 404 patients, respectively) for 6 weeks.2 The primary outcome measure was at least a 30% improvement in pain using a 0 (no pain) to 10 (worst possible pain) scale. In both studies, more patients taking celecoxib had positive responses than patients taking tramadol (63% vs 50%, P<.001, and 64% vs 55%, P<.008, respectively).