BACKGROUND: Some leading German pain medicine experts postulate that there is a type of chronic non-cancer pain (CNCP) with an opioid requirement. We tested whether opioids are superior to nonopioid analgesics in the management of CNCP in studies of at least 4 week's duration.
METHODS: We screened MEDLINE, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL) up until October 2013, as well as the reference sections of original studies and systematic reviews of randomised controlled trials (RCTs) of opioids in CNCP. We included double-blind RTCs comparing opioids to nonopioid analgesics of at least 4 week's duration. Relative risks differences (RD) of categorical data and standardized mean differences (SMD) of continuous variables were calculated using a random effects model.
RESULTS: We included 10 RCTs with 3046 participants. Median study duration was 6 weeks (range 4-12 weeks). Five studies compared tramadol with nonsteroidal anti-inflammatory drugs (NSAIDs) in osteoarthritis pain and one trial compared tramadol to flupirtine in low back pain. Morphine was compared to antidepressants (two studies), an anticonvulsant (one study) and an antiarrhythmic (one study) in different neuropathic pain syndromes. There was no significant difference between opioids and nonopioid analgesics in pain reduction (SMD 0.03 [95 % confidence interval, CI - 0.18, 0.24]; p = 0.76). Nonopioid analgesics were superior to opioids in improving physical function (SMD 0.17 [95 % CI 0.02, 0.32]; p = 0.03). Patients dropped out due to adverse events more frequently with opioids than with nonopioid analgesics (RD 0.09 [95 % CI 0.06, 0.13]; p < 0.0001). There was no significant difference between opioids and nonopioid analgesics in terms of serious adverse events or dropout rates due to lack of efficacy.
CONCLUSION: Nonopioid analgesics are superior to opioids in terms of improvement of physical function and tolerability in short-term (4-12 weeks) therapy of neuropathic, low back and osteoarthritis pain. Our results do not support the concept of an"opioid-requiring" CNCP. The English full-text version of this article is freely available at SpringerLink (under "Supplemental").
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
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.
BACKGROUND: The use of opioids in the long-term management of chronic low-back pain (CLBP) has increased dramatically. Despite this trend, the benefits and risks of these medications remain unclear. This review is an update of a Cochrane review first published in 2007.
OBJECTIVES: To determine the efficacy of opioids in adults with CLBP.
SEARCH METHODS: We electronically searched the Cochrane Back Review Group's Specialized Register, CENTRAL, CINAHL and PsycINFO, MEDLINE, and EMBASE from January 2006 to October 2012. We checked the reference lists of these trials and other relevant systematic reviews for potential trials for inclusion.
SELECTION CRITERIA: We included randomized controlled trials (RCTs) that assessed the use of opioids (as monotherapy or in combination with other therapies) in adults with CLBP that were at least four weeks in duration. We included trials that compared non-injectable opioids to placebo or other treatments. We excluded trials that compared different opioids only.
DATA COLLECTION AND ANALYSIS: Two authors independently assessed the risk of bias and extracted data onto a pre-designed form. We pooled results using Review Manager (RevMan) 5.2. We reported on pain and function outcomes using standardized mean difference (SMD) or risk ratios with 95% confidence intervals (95% CI). We used absolute risk difference (RD) with 95% CI to report adverse effects.
MAIN RESULTS: We included 15 trials (5540 participants). Tramadol was examined in five trials (1378 participants); it was found to be better than placebo for pain (SMD -0.55, 95% CI -0.66 to -0.44; low quality evidence) and function (SMD -0.18, 95% CI -0.29 to -0.07; moderate 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), but no difference compared to placebo for function (SMD -0.14, 95%CI -0.53 to 0.25; very low quality evidence). Strong opioids (morphine, hydromorphone, oxycodone, oxymorphone, and tapentadol), examined in six trials (1887 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). One trial (1583 participants) demonstrated that tramadol may make little difference compared to celecoxib (RR 0.82, 95% CI 0.76 to 0.90; very low quality evidence) for pain relief. Two trials (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). The included trials in this review had high drop-out rates, were of short duration, and had limited interpretability of functional improvement. They did not report any serious adverse effects, risks (addiction or overdose), or complications (sleep apnea, opioid-induced hyperalgesia, hypogonadism). In general, the effect sizes were medium for pain and small for function.
AUTHORS' CONCLUSIONS: There is some evidence (very low to moderate quality) for short-term efficacy (for both pain and function) of opioids to treat CLBP compared to placebo. The very few trials that compared opioids to non-steroidal anti-inflammatory drugs (NSAIDs) or antidepressants did not show any differences regarding pain and function. 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 CLBP.
Some leading German pain medicine experts postulate that there is a type of chronic non-cancer pain (CNCP) with an opioid requirement. We tested whether opioids are superior to nonopioid analgesics in the management of CNCP in studies of at least 4 week's duration.
METHODS:
We screened MEDLINE, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL) up until October 2013, as well as the reference sections of original studies and systematic reviews of randomised controlled trials (RCTs) of opioids in CNCP. We included double-blind RTCs comparing opioids to nonopioid analgesics of at least 4 week's duration. Relative risks differences (RD) of categorical data and standardized mean differences (SMD) of continuous variables were calculated using a random effects model.
RESULTS:
We included 10 RCTs with 3046 participants. Median study duration was 6 weeks (range 4-12 weeks). Five studies compared tramadol with nonsteroidal anti-inflammatory drugs (NSAIDs) in osteoarthritis pain and one trial compared tramadol to flupirtine in low back pain. Morphine was compared to antidepressants (two studies), an anticonvulsant (one study) and an antiarrhythmic (one study) in different neuropathic pain syndromes. There was no significant difference between opioids and nonopioid analgesics in pain reduction (SMD 0.03 [95 % confidence interval, CI - 0.18, 0.24]; p = 0.76). Nonopioid analgesics were superior to opioids in improving physical function (SMD 0.17 [95 % CI 0.02, 0.32]; p = 0.03). Patients dropped out due to adverse events more frequently with opioids than with nonopioid analgesics (RD 0.09 [95 % CI 0.06, 0.13]; p < 0.0001). There was no significant difference between opioids and nonopioid analgesics in terms of serious adverse events or dropout rates due to lack of efficacy.
CONCLUSION:
Nonopioid analgesics are superior to opioids in terms of improvement of physical function and tolerability in short-term (4-12 weeks) therapy of neuropathic, low back and osteoarthritis pain. Our results do not support the concept of an"opioid-requiring" CNCP. The English full-text version of this article is freely available at SpringerLink (under "Supplemental").
Systematic Review Question»Systematic review of interventions
