Opioids in chronic non-cancer pain: systematic review of efficacy and safety
ABSTRACT Opioids are used increasingly for chronic non-cancer pain. Controversy exists about their effectiveness and safety with long-term use. We analysed available randomised, placebo-controlled trials of WHO step 3 opioids for efficacy and safety in chronic non-cancer pain. The Oxford Pain Relief Database (1950-1994) and Medline, EMBASE and the Cochrane Library were searched until September 2003. Inclusion criteria were randomised comparisons of WHO step 3 opioids with placebo in chronic non-cancer pain. Double-blind studies reporting on pain intensity outcomes using validated pain scales were included. Fifteen randomised placebo-controlled trials were included. Four investigations with 120 patients studied intravenous opioid testing. Eleven studies (1025 patients) compared oral opioids with placebo for four days to eight weeks. Six of the 15 included trials had an open label follow-up of 6-24 months. The mean decrease in pain intensity in most studies was at least 30% with opioids and was comparable in neuropathic and musculoskeletal pain. About 80% of patients experienced at least one adverse event, with constipation (41%), nausea (32%) and somnolence (29%) being most common. Only 44% of 388 patients on open label treatments were still on opioids after therapy for between 7 and 24 months. The short-term efficacy of opioids was good in both neuropathic and musculoskeletal pain conditions. However, only a minority of patients in these studies went on to long-term management with opioids. The small number of selected patients and the short follow-ups do not allow conclusions concerning problems such as tolerance and addiction.
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ABSTRACT: To evaluate the efficacy and safety of auricular therapy (AT) on chronic pain. A systematic review. Randomized controlled trials investigating AT for chronic pain were retrieved and RevMan 5.3 was used for meta-analysis. Fifteen trials were included. The overall assessment indicated that AT could be a promising intervention for chronic pain relief. Meta-analyses showed that AT decreased pain intensity, especially for chronic low back pain and chronic tension headache. The lasting effect of AT was not obvious, and it began to diminish 3 months after the completion of treatment. AT may positively control pain intensity for patients with chronic pain. However, due to the significant heterogeneity and methodological flaws identified in the analyzed trials, the current evidence on AT for chronic pain management is still uncertain. More rigorously designed large-scale randomized controlled trials are required to evaluate the efficacy of AT for patients with chronic pain. Copyright © 2015 Elsevier Ltd. All rights reserved.Complementary Therapies in Clinical Practice 04/2015; DOI:10.1016/j.ctcp.2015.03.006
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ABSTRACT: Chronic pain (CP) is a prevalent and disabling diagnosis in obese individuals, but how bariatric surgery patients respond to chronic pain rehabilitation treatment programs has not previously been described. The aim of this study was to compare treatment outcomes of a chronic pain rehabilitation program (psychological and pain variables, medication use, treatment completion rates) for post-bariatric surgery patients to those of a non-bariatric surgery control group. Three week outpatient multidisciplinary chronic pain program in an academic medical center. This was a retrospective case-control study. Medical records of patients admitted to the Pain Rehabilitation Center at Mayo Clinic from 2008 to 2012 were reviewed. One hundred six patients with a history of bariatric surgery (cases) were identified and matched to 106 patients without a history of bariatric surgery (controls) on age, gender, and smoking status (n = 202). Matched t tests and McNemar's tests were used for analyses. Mean age was 46 years; 91 % were female and 58 % were non-smokers. The majority of cases (71 %) had undergone Roux-en-Y gastric bypass. Bariatric patients had higher rates of benzodiazepine use at discharge (33 vs. 19 %, p = 0.0433) and were less likely to complete treatment (87 vs. 97 %, p = 0.007) compared to controls. Morphine equivalent use for cases was 127.3 mg ± 135.4 (n = 62) compared to 88.3 mg ± 95.3 (n = 62), p = 0.12, for controls at admission. These results suggest that bariatric patients may be at risk for treatment non-adherence and have difficulty reducing medication use in the treatment of chronic pain.
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ABSTRACT: Opioids rank among the most potent analgesic drugs but gastrointestinal side effects, especially constipation, limit their therapeutic utility. The adverse effects of opioids have been attributed to stimulation of opioid receptors, but emerging evidence suggests that opioids interact with the innate immune receptor Toll-like receptor 4 (TLR4) and its signalling pathway. As TLR4 signalling affects gastrointestinal motility, we examined the involvement of TLR4 in morphine-induced depression of peristaltic motility in the guinea-pig intestine in vitro and male C57BL/6N mice in vivo. While the TLR4 antagonist TAK-242 (0.1 μM and 1 μM) did not alter the morphine-induced inhibition of peristalsis in the isolated guinea-pig small intestine, the morphine-induced decrease in pellet propulsion velocity in colonic segments was attenuated by TAK-242 (0.1 μM). The ability of TAK-242 (4 mg/kg) to mitigate the morphine-induced suppression of colonic motility was replicated in mice in vivo by measuring the expulsion time of beads inserted in the distal colon. The inhibition of upper gastrointestinal transit of mice by morphine was not affected by pre-treatment with TAK-242 (4 mg/kg) in vivo. This is the first report that morphine-induced inhibition of colonic peristalsis is alleviated by TLR4 antagonism. We therefore conclude that TLR4 may contribute to opioid-induced constipation.