[Opioids in chronic noncancer pain-are opioids different? A systematic review and meta-analysis of efficacy, tolerability and safety in randomized head-to-head comparisons of opioids of at least four week's duration]

Time to initiate randomized controlled clinical trials with methadone in cancer patients

Public media coverage has fueled a demand for methadone as potential cure for cancer itself. Because patients have asked for respective prescriptions, clinical societies issued statements warning against the use of methadone as long as preclinical findings have not been supported by clinical evidence. In fact, not all preclinical data clearly support relevant effects. However, strong epidemiologic data suggest beneficial effects of methadone on cancer. Alternative explanations, namely better safety of methadone or hidden selection bias, seem less likely. This uncertainty can only be resolved by randomized controlled clinical trials. This review discusses all relevant data pertinent to methadone and cancer, uncovers supportive epidemiologic data, and suggests possible study designs.

Tapentadol: an overview of the safety profile

Long-term opioid therapy may be associated with analgesic efficacy and also predictable adverse events, including cardiovascular and pulmonary events, gastrointestinal disorders, endocrinological harms, psychological problems, impairment of driving ability, and risk of abuse. These effects of opioids are mostly due to the wide expression of the mu receptor. Tapentadol, a centrally acting analgesic, is the first agent of a new class of drugs (MOR-NRI), since it combines two mechanisms of action, namely µ-opioid receptor (MOR) agonism and noradrenaline reuptake inhibition. Noteworthy, MOR activation with tapentadol is markedly lower compared with that exerted by classical opioids, thus likely resulting in fewer opioid-related adverse effects. In this review, we discuss current safety data on tapentadol, with a focus on some specific events, risk of abuse, and driving ability, a well-accepted proxy of the ability of taking critical decisions.

[Incidence of constipation in patients with outpatient opioid therapy]

BACKGROUND

Constipation is a common complication in patients with opioid therapy. Additionally, patient-related risk factors also contribute to the development of constipation and these factors have to be integrated into an individualized treatment plan.

OBJECTIVE

The aim of this study was to assess the incidence of constipation in patients with opioid therapy in an outpatient setting and to analyze the risk factors that contribute to the development of constipation.

MATERIAL AND METHODS

This retrospective cohort study was conducted in two university affiliated outpatient departments at the Charité hospital in Berlin. The trial included all consecutively treated patients with opioid therapy of at least 4 weeks duration. The study was conducted from January 2013 to August 2013. Constipation was defined according to the Rome III criteria.

RESULTS

Out of 1166 screened patients, altogether 171 patients were included with a median duration of opioid therapy of 5 years. The most common diagnoses were back pain, musculoskeletal pain and neuropathic pain. In 14% of the treated patients symptoms of constipation were detected and another 35% needed laxatives for symptom control resulting in an overall incidence of constipation of 49%. The remaining 51% of the patients did not use any laxatives and did not experience symptoms of constipation. Age and dosing of opioid therapy significantly increased the risk of consipation but duration of opioid therapy was not related to the incidence of constipation.

DISCUSSION

The incidence of constipation in this population remains high although a relevant number of patients were intermittently free of symptoms without using laxatives. An individualized therapy plan and patient education seem to be important elements to control opioid-associated constipation.

[Opioids for noncancer pain in the elderly]

BACKGROUND

Opioids are increasingly used in the elderly. Side effects differ compared to other analgesics.

PURPOSE

In this review article, special aspects about using opioids for noncancer pain in older people and in geriatric patients are identified.

CURRENT SITUATION

So far randomized controlled trials for the indication of and comparison between various opioids have been performed in middle-aged patients and not exclusively in geriatric patients or elderly (> 75 years). Furthermore, the evidence for multimorbid elderly patients with respect to side effects is also very poor.

RECOMMENDATIONS

The indication for opioid therapy should be narrow. The patient and their caregivers must be provided patient information regarding opioid therapy. The principle "start low, go slow" is highly recommended. To reduce the risk of falls, longer acting opioids should be used and short acting opioids should be avoided. Everyday relevant negative effects on cognition are possible in opioid use and have to be observed. As recommended in the recently published German guideline for long-term use of opioids in noncancer pain a critical check after 3 months and in case of dosing over 120 mg morphine equivalents is advisable, especially for older patients. Liver and kidney function and drug interactions have to be taken into consideration like in every age group.

[S3 guidelines on long-term opioid treatment in non-cancer pain. Recommendations for opioid use in clinical rheumatology]

The long-term use of opioids for chronic pain can be problematic in many respects. Besides potentially harmful and considerable undesired side effects and possible drug abuse, the indications for prescription, efficacy and safety in the long run have to be considered. The recently updated S3 guidelines on long-term opioid treatment in non-cancer pain (LONTS) provide recommendations with the highest currently available evidence. This article summarizes the most relevant contents for the clinical rheumatologist.

[Long-term opioid therapy in chronic noncancer pain. A systematic review and meta-analysis of efficacy, tolerability and safety in open-label extension trials with study duration of at least 26 weeks]

BACKGROUND

The efficacy and safety of long-term (≥ 6 months) opioid therapy (LtOT) in chronic noncancer pain (CNCP) is under debate. A systematic review with meta-analysis of the efficacy and harms of opioids in open-label extension studies of randomized controlled trials (RCTs) has not been conducted until now.

METHODS

We screened MEDLINE and clinicaltrials.gov (through to December 2013), as well as reference sections of systematic reviews of long-term RCTs of opioids in CNCP. We included open-label extension trials with a study duration ≥ 26 weeks of RCTs of ≥ 2 weeks duration. Using a random effects model, pooled estimates of event rates for categorical data and standardized mean differences (SMD) for continuous variables were calculated.

RESULTS

We included 11 open-label extension studies with 2445 participants with nociceptive (low back, osteoarthritis) and neuropathic (radicular, polyneuropathy) pain. Median study duration was 26 (range 26-108) weeks. Four studies tested oxycodone, two studies tramadol and buprenorphine; hydromorphone, morphine, oxymorphone and tapentadol were each tested in one study. Of the patients randomized at baseline, 28.5 % (95 % confidence interval, CI, 17.9-39.2 %) finished the open-label period; 53.5 % (95 % CI 38.1-68.2 %) of patients entering the open-label period finished the open-label period. In sum, the total loss was 71.5 % (95 % CI 60.9-83.1 %) of all patients primarily included into the RCT. A total of 4.9 % (95 % CI 2.9-8.2 %) of patients dropped out due lack of efficacy; 16.8 % (95 % CI 11.0-24.8 %) dropped out to due adverse events (AE) in the open-label period and 0.08 % (95 % CI 0.001-0.05 %) of patients died during the open-label period. Only one study systematically assessed aberrant drug behavior of the patients: 5.7 % (95 % CI 3.4-9.6 %) showed aberrant drug behavior in the opinion of the investigators and 2.6 % (95 % CI 1.2-5.8 %) were judged to show aberrant drug behavior by independent expert assessment. There was no significant change (p = 0.50) in pain intensity between the end of the randomized period and the end of open-label phase (SMD 0.19 [- 0.03, 0.41]; six studies with 1360 participants).

CONCLUSION

Only a minority of patients selected for opioid therapy at randomization finished the long-term open-label study. However, sustained effects of pain reduction could be demonstrated in these patients. LtOT can be considered in carefully selected and monitored CNCP patients who experience clinically meaningful pain reduction with at least tolerable AE in short-term opioid therapy. The English full-text version of this article is freely available at SpringerLink (under "Supplementary Material").

[Methodology of the development of the updated LONTS guidelines for long-term administration of opioids in noncancer pain]

BACKGROUND

The update of the German S3 guidelines on long-term opioid therapy of chronic noncancer pain (CNCP), the"LONTS" (AWMF registration number 145/003) was scheduled for May 2014.

METHODS

The guidelines were developed by 25 scientific societies and two patient self-help organizations under the coordination of the German Pain Society and the Association of the Scientific Medical Societies in Germany (AWMF).

RESULTS

A systematic literature search was performed in the CENTRAL, MEDLINE and Scopus databases from October 2008 to October 2013. Meta-analyses of randomized controlled trials (RCT) of opioids in CNPC of study duration ≥ 4 weeks were conducted. Levels of evidence were assigned according to the Oxford Centre for Evidence-Based Medicine version 2009 classification system. The formulation and strength of recommendations was established in a multistep formalized consensus procedure, in accordance with AWFM rules and standards. The guidelines were reviewed by three scientific societies not involved in their development and were approved by the executive boards of the societies that were engaged in development of the guidelines.

CONCLUSION

The guidelines will be published in several forms: complete and short scientific versions, as well as clinical practice and patient versions.

[Recommendations of the updated LONTS guidelines. Long-term opioid therapy for chronic noncancer pain]

BACKGROUND

The regular update of the German S3 guidelines on long-term opioid therapy for chronic noncancer pain (CNCP), the"LONTS" (AWMF registration number 145/003), began in November 2013.

METHODS

The guidelines were developed by 26 scientific societies and two patient self-help organisations under the coordination of the Deutsche Schmerzgesellschaft (German Pain Society). A systematic literature search in the Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Scopus databases (up until October 2013) was performed. Levels of evidence were assigned according to the classification system of the Oxford Centre for Evidence-Based Medicine. The strength of the recommendations was established by multistep formal procedures, in order to reach a consensus according to German Association of the Medical Scientific Societies ("Arbeitsgemeinschaft der Wissenschaftlich Medizinischen Fachgesellschaften", AWMF) regulations. The guidelines were reviewed by the Drug Commission of the German Medical Association, the Austrian Pain Society and the Swiss Association for the Study of Pain.

RESULTS

Opioids are one drug-based treatment option for short- (4-12 weeks), intermediate- (13-25 weeks) and long-term (≥ 26 weeks) therapy of chronic osteoarthritis, diabetic polyneuropathy, postherpetic neuralgia and low back pain. Contraindications are primary headaches, as well as functional somatic syndromes and mental disorders with the (cardinal) symptom pain. For all other clinical presentations, a short- and long-term therapy with opioid-containing analgesics should be evaluated on an individual basis. Long-term therapy with opioid-containing analgesics is associated with relevant risks (sexual disorders, increased mortality).

CONCLUSION

Responsible application of opioid-containing analgesics requires consideration of possible indications and contraindications, as well as regular assessment of efficacy and adverse effects. Neither an uncritical increase in opioid application, nor the global rejection of opioid-containing analgesics is justified in patients with CNCP.

Efficacy and tolerability balance of oxycodone/naloxone and tapentadol in chronic low back pain with a neuropathic component: a blinded end point analysis of randomly selected routine data from 12-week prospective open-label observations

Objective

To evaluate the benefit–risk profile (BRP) of oxycodone/naloxone (OXN) and tapentadol (TAP) in patients with chronic low back pain (cLBP) with a neuropathic component (NC) in routine clinical practice.

Methods

This was a blinded end point analysis of randomly selected 12-week routine/open-label data of the German Pain Registry on adult patients with cLBP-NC who initiated an index treatment in compliance with the current German prescribing information between 1st January and 31st October 2015 (OXN/TAP, n=128/133). Primary end point was defined as a composite of three efficacy components (≥30% improvement of pain, pain-related disability, and quality of life each at the end of observation vs baseline) and three tolerability components (normal bowel function, absence of either central nervous system side effects, and treatment-emergent adverse event [TEAE]-related treatment discontinuation during the observation period) adopted to reflect BRP assessments under real-life conditions.

Results

Demographic as well as baseline and pretreatment characteristics were comparable for the randomly selected data sets of both index groups without any indicators for critical selection biases. Treatment with OXN resulted formally in a BRP noninferior to that of TAP and showed a significantly higher primary end point response vs TAP (39.8% vs 25.6%, odds ratio: 1.93; P=0.014), due to superior analgesic effects. Between-group differences increased with stricter response definitions for all three efficacy components in favor of OXN: ≥30%/≥50%/≥70% response rates for OXN vs TAP were seen for pain intensity in 85.2%/67.2%/39.1% vs 83.5%/54.1%/15.8% (P= ns/0.031/<0.001), for pain-related disability in 78.1%/64.8%/43.8% vs 66.9%/50.4%/24.8% (P=0.043/0.018/0.001), and for quality of life in 76.6%/68.0%/50.0% vs 63.9%/54.1%/34.6% (P=0.026/0.022/0.017). Overall, OXN vs TAP treatments were well tolerated, and proportions of patients who either maintained a normal bowel function (68.0% vs 72.2%), reported no central nervous system side effects (91.4% vs 89.5%), or completed the 12-week evaluation period without any TEAE-related treatment discontinuations (93.0% vs 92.5%) were similar for both index medications (P= ns for each comparison).

Conclusion

In daily practice, the BRP of OXN proved to be noninferior to that of TAP in patients with cLBP-NC, but showed a superior efficacy if stricter analgesic response definitions were evaluated.

Quality of life under oxycodone/naloxone, oxycodone, or morphine treatment for chronic low back pain in routine clinical practice

OBJECTIVE

To compare the quality of life of patients with moderate-to-severe chronic low back pain under treatment with the WHO-step III opioids oxycodone/naloxone, oxycodone, or morphine in routine clinical practice.

STUDY DESIGN

Prospective, 12-week, randomized, open-label, blinded end-point study in 88 medical centers in Germany.

PATIENTS AND METHODS

A total of 901 patients requiring around-the-clock pain treatment with a WHO-step III opioid were randomized to either morphine, oxycodone, or oxycodone/naloxone (1:1:1). Changes from baseline to week 12 in quality of life were assessed using different validated tools (EuroQoL-5 Dimensions [EQ-5D], Short Form 12 [SF-12], quality of life impairment by pain inventory [QLIP]).

RESULTS

EQ-5D weighted index scores significantly improved over the 12-week treatment period under all three opioids (P<0.001) with significantly greater improvements under oxycodone/naloxone (65.2% vs 49.6% for oxycodone and 48.2% for morphine, P<0.001). The proportion of patients without EQ-5D complaints was also significantly higher under oxycodone/naloxone (P<0.001). Although quality of life ratings with the QLIP inventory showed significant improvements in all the three treatment arms, improvements were significantly higher under oxycodone/naloxone than under oxycodone and morphine (P<0.001): 90.7% of all oxycodone/naloxone patients achieved ≥30% improvements in quality of life, 72.8% had ≥50%, and 33.2% ≥70% improvements. Similarly, both physical and mental SF-12 component scores showed significantly greater improvements under oxycodone/naloxone with both scores close to the German population norm after 12 weeks.

CONCLUSION

Treatment with morphine, oxycodone, or oxycodone/naloxone under routine daily practice conditions significantly improved state of health and quality of life of patients with moderate-to-severe low back pain over a 12-week treatment period. Comparison between the treatment groups showed significantly greater improvements for oxycodone/naloxone than for the other two opioids.

Meta-analyses of pain studies: What we have learned

Meta-analysis is a statistical procedure that integrates the results of at least two independent studies. The biggest threats to meta-analysis are publication bias due to missing studies with negative results and low-quality evidence due to methodological limitations imposed by included studies. Tools to improve the quality of meta-analysis have been developed by the Cochrane Collaboration and by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Meta-analyses of trials have demonstrated that pain responses in patients with chronic pain, following treatment, are not normally distributed but have a bimodal distribution with the majority of patients having either very little or very good pain relief. The benefit can be detected within 2-4 weeks following drug administration. Further, the efficacy of drug and physical treatments is hampered by high placebo response rates, with modest average benefits with active treatments over placebo in both parallel and crossover design trials.

Long-term opioid use in non-cancer pain

BACKGROUND

The long-term use of opioid analgesic drugs to treat chronic non-cancer pain (CNCP) is a major component of pain pharmacotherapy. The interpretation of the evidence concerning its efficacy and risks is currently debated.

METHODS

An interdisciplinary evidence- and consensus-based S3 guideline was updated on the basis of a systematic literature search (CENTRAL, Medline, and Scopus databases, from October 2008 to October 2013); meta-analyses of randomized controlled trials (≥ 4 weeks); and a consensus procedure, as specified by the AWMF regulations, including 22 medical and psychological societies and 2 patient self-help organizations.

RESULTS

119 publications were used to update the guideline, and 6 systematic reviews with meta-analyses were performed. A nominal group process was used to formulate recommendations concerning the indications and contraindications for the treatment of CNCP with opioid analgesics and the manner in which such treatments should be carried out. Opioid analgesics are an option for the short-term treatment (4-12 weeks) of chronic pain due to osteoarthritis (pain intensity, standardized mean difference [SMD]: -0.22 and -0.26), diabetic polyneuropathy (SMD -0.74), post-herpetic neuralgia (SMD -0.58), and chronic low back pain (SMD: -0.29 and -0.74). Long-term opioid treatment (≥ 26 weeks) for these diseases benefits only about 25% of patients. For other conditions, either short- or long-term treatment with opioid analgesics should be considered an individual therapeutic trial. Opioid treatment for pain is contraindicated by primary headaches and by any functional or mental disorder of which pain is a leading manifestation.

CONCLUSION

To minimize the risks of opioid analgesic treatment, physicians must be aware of its contraindications and must regularly reassess its efficacy and side effects. Pharmacotherapy should be combined with other types of treatment.