BACKGROUND: The efficacy and safety of opioid therapy in chronic @entity9 (CNP) is under debate. We updated a recent Cochrane systematic review on the efficacy, tolerability and safety of opioids in CNP. 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 randomized controlled trials (RCTs) of opioids in CNP. We included double-blind randomized placebo-controlled studies of at least 4  weeks duration. Using a random effects model, absolute risk differences (RD) were calculated for categorical data and standardized mean differences (SMD) for continuous variables. RESULTS: We included 12  RCTs with 1192  @entity1 . The included diagnostic entities were @entity3949 (four studies), @entity14000 (three studies), mixed @entity158 (two studies), and lumbar root, @entity1566 and postamputation @entity158 (one study each). Mean study duration was 6  (4-12)  weeks. Four studies tested @entity1286 , three studies tramadol, two studies @entity1288 and one study @entity20708 . These are the pooled results of studies with a parallel or cross-over design: opioids were superior to placebo in reducing @entity158 intensity (SMD -   0.64 [95   % confidence interval, CI  -   0.81,  -   0.46], p   <   0.0001; 11  studies with 1040  @entity1 ). Opioids were not superior to placebo in 50   % @entity158 reduction (RD  0.16 [95   %  CI  -   0.04,  0.35], p   =   0.11; one study with 93  @entity1 ). Opioids were not superior to placebo in reports of much or very much improved @entity158 (RD  0.17 [95   %  CI  -   0.01,  0.36], p   =   0.07; one study with 53  @entity1 ). Opioids were superior to placebo in improving physical functioning (SMD  -   0.28 [95   %  CI  -   0.43,  -   0.13], p   <   0.0001; seven studies with 680  @entity1 ). @entity1 dropped out less frequently due to lack of efficacy with opioids than with placebo (RD  -   0.07 [95   %  CI  -   0.13,  -   0.02], p   =   0.008; six studies with 656  @entity1 ). @entity1 dropped out due to adverse events more frequently with opioids than with placebo (RD  0.08 [95   %  CI  0.05,  0.12], p   <   0.0001; ten studies with 1018  @entity1 ; number needed to harm  11 [95   %  CI  8-17]). There was no significant difference between opioids and placebo in terms of the frequency of serious adverse events (SAE) or @entity204 . CONCLUSION: In short-term studies (4-12  weeks) in CNP, opioids were superior to placebo in terms of efficacy and inferior in terms of tolerability. Opioids and placebo did not differ in terms of safety. The conclusion relating to the safety of opioids compared to placebo in CNP is limited by the low number of SAE and @entity204 . Short-term opioid therapy may be considered in selected CNP @entity1 . The English full-text version of this article is freely available at SpringerLink (under "Supplementary Material").

[Opioids in chronic XXXX : A systematic review and meta-analysis of efficacy, tolerability and safety in randomized placebo-controlled studies of at least 4  weeks duration.]

@entity1 :: ('9606', 'Species') :: ['participants', 'Patients', 'patients'] @entity1288 :: ('MESH:D010098', 'Chemical') :: ['oxycodone'] @entity3949 :: ('MESH:D003929', 'Disease') :: ['painful diabetic neuropathy'] @entity20708 :: ('MESH:C523979', 'Chemical') :: ['tapentadol'] @entity158 :: ('MESH:D010146', 'Disease') :: ['polyneuropathic pain', 'pain'] @entity1286 :: ('MESH:D009020', 'Chemical') :: ['morphine'] @entity1566 :: ('MESH:D013119', 'Disease') :: ['spinal cord injury'] @entity14000 :: ('MESH:D051474', 'Disease') :: ['postherpetic neuralgia'] @entity204 :: ('MESH:D003643', 'Disease') :: ['deaths'] @entity9 :: ('MESH:D009437', 'Disease') :: ['neuropathic pain']
@entity9 :: (MESH:D009437,Disease) :: ['neuropathic pain']
