There is very low to moderate quality evidence for short-term use of opioids to treat chronic lower back pain compared to placebo, according to an updated review of the literature.
To determine the efficacy of opioids in adults with chronic lower back pain, researchers reviewed 15 randomized controlled trials (5,540 participants) all at least four weeks in duration that assessed opioids as monotherapy or in combination with other therapies. The trials all compared non-injectable opioids to placebo or other treatments, and were excluded if they only compared different opioids.
Most people included in the trials were aged 40 to 50 years and all reported at least moderate low-back pain. Most of the trials were supported by the pharmaceutical industry.
Results appeared online Aug. 27 at The Cochrane Library.
The review concluded that tramadol (five trials; 1,378 participants) was better than placebo for pain (standardized mean difference [SMD], -0.55; 95% confidence interval [CI], -0.66 to -0.44; low quality evidence) and function (SMD -0.18, 95% CI -0.29 to -0.07; moderate quality evidence). One other trial with 1,583 participants demonstrated that tramadol compared to celecoxib showed little difference for pain relief (RR, 0.82; 95% CI, 0.76 to 0.90; very low quality evidence).
Transdermal buprenorphine (two trials, 653 participants) may make little difference for pain (SMD, -2.47; 95% CI, -2.69 to -2.25; very low quality evidence). There was no difference compared to placebo for function (SMD, -0.14; 95% CI -0.53 to 0.25; very low quality evidence).
Strong opioids such as morphine, hydromorphone, oxycodone, oxymorphone, and tapentadol (six trials; 1,887 participants), were better than placebo for pain (SMD, -0.43; 95% CI -0.52 to -0.33; moderate quality evidence) and function (SMD, -0.26; 95% CI -0.37 to -0.15; moderate quality evidence).
Two trials with 272 participants found no difference between opioids and antidepressants for either pain (SMD, 0.21; 95% CI -0.03 to 0.45; very low quality evidence) or function (SMD, -0.11; 95% -0.63 to 0.42; very low quality evidence).
Researchers noted that people who received opioids reported more pain relief and had less difficulty with daily activities in the short-term, but there is little data based on objective measures of physical functioning. There is no information supporting safety and efficacy beyond four months. The review did not show that opioids are more effective than other analgesics, such as anti-inflammatories or antidepressants, for low-back pain.
They wrote, “The initiation of a trial of opioids for long-term management should be done with extreme caution, especially after a comprehensive assessment of potential risks. There are no placebo-RCTs supporting the effectiveness and safety of long-term opioid therapy for treatment of chronic lower back pain.”