Friday, April 4, 2014
Opioids for Chronic Low Back Pain? Results From the Latest Cochrane Review
The use of opioids in the treatment of chronic low back pain (CLBP) is controversial due to a lack of evidence regarding the efficacy and adverse effects associated with their use for this indication. Initially, opioids tended to be used only for patients with cancer pain or those with acute pain related to surgery or trauma, but the pendulum swung towards their use for chronic non-cancer pain in the 1990s. More recently, concern over long-term adverse effects such as tolerance, addiction, and overdose, not to mention abuse and diversion, has caused the pendulum to swing back against their use for chronic non-cancer pain. In an effort to add an evidence base to the discussion, Dr. Chaparro and an accomplished group of co-authors updated the Cochrane Review on the topic of opioids for CLBP, which was published in the April 1 issue. They included blinded RCTs comparing opioids to placebo or other medication in an outpatient setting for patients reporting CLBP (defined as greater than 12 weeks) with a follow-up period of at least 1 month. They included fifteen trials with a total of 5,540 patients that studied “strong opioids” (i.e. morphine, oxycodone, oxymorphone, hydromorphone, tapentadol), tramadol, and transdermal buprenorphine. Their meta-analyses indicated that there was very low to moderate quality evidence that strong opioids, tramadol, and transdermal buprenorphine led to more improvement in pain and function than placebo, with the best quality evidence in support of strong opioids and tramadol. There were few studies comparing opioids to an active control, and these did not show any significant benefit for opioids compared to celecoxib or antidepressants. Not surprisingly, opioids had a worse side effect profile than placebo and were associated with nausea, somnolence, dizziness, and dry mouth. No serious adverse events were reported.
The main conclusion of this review, that opioids were more effective than placebo for short-term treatment of CLBP, is not surprising. Opioids have strong analgesic properties in the short-term, and patient blinding may not have been very effective given the analgesic benefit from opioids as well as the significant side effect profile. The more pressing question is not if opioids are more effective than placebo in treating CLBP in the short term but whether or not opioids are more effective than alternative treatments in the long term. Given that long term opioid use is associated both with tolerance and decreased efficacy as well as potential adverse effects, it seems unlikely that the short term benefit and absence of serious adverse effects reported here would persist in the long term. The real question is whether or not opioids provide better long term outcomes than other potentially less risky alternatives such as anti-inflammatory medication and physical therapy. Now that there are serious concerns about the negative long term effects of opioid therapy, it is unclear whether a study comparing the long term outcomes between opioids and alternative therapies is ethical. Rather than performing such a study, it may simply be time for the spine community to abandon the use of strong opioid medication for CLBP and focus on alternative strategies that can hopefully be more effective and less dangerous.
Please read Dr. Chaparro’s article in the April 1 issue. Does this change you view about the role of opioids in the treatment of CLBP? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
Associate Web Editor