Effect of nebulized morphine on dyspnea of mustard gas-exposed patients: a double-blind randomized clinical trial study

Effectiveness and safety of opioids on breathlessness and exercise endurance in patients with chronic obstructive pulmonary disease: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Opioids are recommended to treat advanced refractory dyspnoea despite optimal therapy by the American Thoracic Society clinical practice guidelines, while newly published randomised controlled trials of opioids in chronic obstructive pulmonary disease yield conflicting results.

AIM

This study aimed to evaluate the effectiveness and safety of opioids for patients with chronic obstructive pulmonary disease.

DESIGN

Systematic review and meta-analysis (PROSPERO CRD42021272556).

DATA SOURCES

Databases of PubMed, EMBASE and CENTRAL were searched from inception to 2022 for eligible randomised controlled trials.

RESULTS

Twenty-four studies including 975 patients, were included. In cross-over studies, opioids improved breathlessness (standardised mean difference, -0.43; 95% CI, -0.55 to -0.30; I2 = 18%) and exercise endurance (standardised mean difference, 0.22; 95% CI, 0.02-0.41; I2 = 70%). However, opioids failed to improve dyspnoea (standardised mean difference, -0.02; 95% CI, -0.22 to 0.19; I2 = 39%) and exercise endurance (standardised mean difference, 0.00; 95% CI, -0.27 to 0.27; I2 = 0%) in parallel control studies that administered sustained-release opioids for more than 1 week. The opioids used in most crossover studies were short-acting and rarely associated with serious adverse effects. Only minor side effects such as dizziness, nausea, constipation and vomiting were identified for short-acting opioids.

CONCLUSIONS

Sustained-release opioids did not improve dyspnoea and exercise endurance. Short-acting opioids appeared to be safe, have potential to lessen dyspnoea and improve exercise endurance, supporting benefit in managing episodes of breathlessness and providing prophylactic treatment for exertional dyspnoea.

Efficacy and Safety of Topical Morphine: A Narrative Review

Background. Opioids are the cornerstone of the therapy used in both acute and chronic pain syndromes to treat pain of moderate to severe intensity. The knowledge that opioid receptors also occur in other tissues outside the central nervous system has created a possibility for the topical use of opioids. Thus, local analgesia may be obtained without systemic adverse effects. Methods. A narrative review of scientific papers discussing the topical use of morphine was conducted. For this purpose, the PubMed, Google Scholar, Cochrane Library, and Mendeley databases were searched. Results. The current knowledge on topical morphine does not allow for its recommended use in everyday medical practice, but suggests it may be effective, particularly in the treatment of ulcers and erosions of inflammatory etiology and painful skin lesions including persistent post-mastectomy pain due to breast cancer. Conclusions. Topical morphine has its place beside other analgesics. An important issue is the practical possibility to meet the demand for topical formulations, which is limited by technical difficulties.

Effect of low dose nebulized morphine on respiratory function improvement in mustard gas-exposed patients: A double-blind crossover clinical trial study

Background

Mustard is one of the most destructive chemical gases used in chemical warfare. Several studies showed effectiveness of inhaled morphine as a secondary treatment for the improvement of dyspnea. Therefore, this study aimed at determining the efficacy of low dose inhaled morphine for respiratory function improvement in patients who were exposed to the mustard gas.

Methods

This study was designed as a cross-over double-blinded clinical trial. Patients exposed to mustard gas were randomly assigned into two groups: 1) received 0.4 mg of morphine by inhalation and 2) received 5 ml of normal saline serum as a placebo in the same manner. After a washout period of one week, the first group received the placebo and the second group received morphine for 5 days. Spirometric indices, expiratory flow peak, exercise test, severity of dyspnea, and quality of life were evaluated as respiratory function parameters. Data analysis was done using SPSS software Version 16.

Results

The mean maximum expiratory flow was significantly higher among cases who used morphine in comparison with the placebo group (p<0.05). Moreover, the severity of dyspnea, quality of life, and the frequency of coughing during the day were significantly improved among the recipients of morphine (p<0.05) while the spirometric indices and exercise tolerance tests were similar between the two groups (p>0.05), but the mean peak expiratory flow (PEFR) was significantly higher among the patients receiving morphine than the placebo patients (p<0.001).

Conclusion

The use of inhaled morphine had a significant positive effect on the respiratory system of people exposed to mustard gas. We can use low doses of inhaled morphine to improve the respiratory function of these patients as a secondary therapy.

A critical review of the respiratory benefits and harms of orally administered opioids for dyspnea management in COPD

INTRODUCTION

Dyspnea occurring in chronic obstructive pulmonary disease (COPD) that is refractory to traditional management strategies is a common and challenging problem. Considerable attention has been paid to the off-label use of orally administered opioids as a pharmacotherapy option for refractory dyspnea in COPD. Multiple professional respiratory society guidelines express support for the application of oral opioids for this purpose.

AREAS COVERED

This manuscript will critically review randomized controlled trials undertaken to date that evaluate the efficacy of oral opioids for dyspnea in COPD, as well as phase IV observational studies that examine for potential opioid-related respiratory harms in the COPD population (literature was searched on PubMed up to June 2021). COPD guideline recommendations relating to opioids for dyspnea will subsequently be critiqued.

EXPERT OPINION

Opioid efficacy trials demonstrate at best a small improvement in dyspnea in limited numbers of individuals with COPD, whereas safety trials consistently show an increased risk of respiratory-related exacerbation, hospitalization and death in association with opioid use. In contrast to what is expressed in guidelines, the current body of evidence does not the support the wide application of opioids to manage refractory dyspnea among individuals with COPD, but instead, a highly selective and careful approach.

Cost-effectiveness of sustained-release morphine for refractory breathlessness in COPD: A randomized clinical trial

BACKGROUND

Chronic breathlessness is a frequent symptom in advanced Chronic Obstructive Pulmonary Disease (COPD) and has major impact on quality of life, daily activities and healthcare utilization. Morphine is used as palliative treatment of chronic breathlessness. The aim is to analyze cost-effectiveness of regular, low-dose morphine in patients with advanced COPD from a healthcare and societal perspective.

METHODS

In a randomized controlled trial, participants with advanced COPD were assigned to 10 mg regular, oral sustained-release morphine or placebo twice daily for four weeks. Quality of life (COPD Assessment Test; CAT), quality-adjusted life years (QALY's; EQ-5D-5L), healthcare costs, productivity, and patient and family costs were collected. Incremental cost-effectivity ratio's (ICERs) using healthcare costs and CAT scores, and incremental cost-utility ratio's (ICURs) using societal costs and QALY's were calculated.

RESULTS

Data of 106 of 124 participants were analyzed, of which 50 were in the morphine group (mean [SD] age 65.4 [8.0] years; 58 [55%] male). Both ICER and ICUR indicated dominance for morphine treatment. Sensitivity analyses substantiated these results. From a healthcare perspective, the probability that morphine is cost-effective at a willingness to pay €8000 for an minimal clinically important difference of 2 points increase in CAT score is 63%. From a societal perspective, the probability that morphine is cost-effective at a willingness to pay €20,000 per QALY is 78%.

CONCLUSION

Morphine for four weeks is cost-effective regarding the healthcare and the societal perspective. To estimate the long-term costs and effects of morphine treatment, a study of longer follow-up should be performed.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02429050).

Pharmacologic Management of Chronic Obstructive Pulmonary Disease. An Official American Thoracic Society Clinical Practice Guideline

Background: This document provides clinical recommendations for the pharmacologic treatment of chronic obstructive pulmonary disease (COPD). It represents a collaborative effort on the part of a panel of expert COPD clinicians and researchers along with a team of methodologists under the guidance of the American Thoracic Society.

Methods: Comprehensive evidence syntheses were performed on all relevant studies that addressed the clinical questions and critical patient-centered outcomes agreed upon by the panel of experts. The evidence was appraised, rated, and graded, and recommendations were formulated using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

Results: After weighing the quality of evidence and balancing the desirable and undesirable effects, the guideline panel made the following recommendations: 1) a strong recommendation for the use of long-acting β₂-agonist (LABA)/long-acting muscarinic antagonist (LAMA) combination therapy over LABA or LAMA monotherapy in patients with COPD and dyspnea or exercise intolerance; 2) a conditional recommendation for the use of triple therapy with inhaled corticosteroids (ICS)/LABA/LAMA over dual therapy with LABA/LAMA in patients with COPD and dyspnea or exercise intolerance who have experienced one or more exacerbations in the past year; 3) a conditional recommendation for ICS withdrawal for patients with COPD receiving triple therapy (ICS/LABA/LAMA) if the patient has had no exacerbations in the past year; 4) no recommendation for or against ICS as an additive therapy to long-acting bronchodilators in patients with COPD and blood eosinophilia, except for those patients with a history of one or more exacerbations in the past year requiring antibiotics or oral steroids or hospitalization, for whom ICS is conditionally recommended as an additive therapy; 5) a conditional recommendation against the use of maintenance oral corticosteroids in patients with COPD and a history of severe and frequent exacerbations; and 6) a conditional recommendation for opioid-based therapy in patients with COPD who experience advanced refractory dyspnea despite otherwise optimal therapy.

Conclusions: The task force made recommendations regarding the pharmacologic treatment of COPD based on currently available evidence. Additional research in populations that are underrepresented in clinical trials is needed, including studies in patients with COPD 80 years of age and older, those with multiple chronic health conditions, and those with a codiagnosis of COPD and asthma.

Opioids for breathlessness: a narrative review

Chronic breathlessness is a disabling and distressing condition for which there is a growing evidence base for a range of interventions. Non-pharmacological interventions are the mainstay of management and should be optimised prior to use of opioid medication. Opioids are being implemented variably in practice for chronic breathlessness. This narrative review summarises the evidence defining current opioids for breathlessness best practice and identifies remaining research gaps. There is level 1a evidence to support the use of opioids for breathlessness. The best evidence is for 10–30 mg daily de novo low-dose oral sustained-release morphine in opioid-naïve patients. This should be considered the current standard of care following independent, regulatory scrutiny by one of the world’s therapeutics regulatory bodies. Optimal benefits are seen in steady state; however, there are few published data about longer term benefits or harms. Morphine-related adverse events are common but mostly mild and self-limiting on withdrawal of drug. Early and meticulous management of constipation, nausea and vomiting is needed particularly in the first week of administration. Serious adverse events are no more common than placebo in clinical studies. Observational studies in severe chronic lung disease do not show excess mortality or hospital admission in those taking opioids. We have no long-term data on immune or endocrine function. There are promising data regarding prophylaxis for exertion-related breathlessness, but given the risks associated with transmucosal fentanyl, caution is needed with regard to clinical use pending longer term, robust safety data.

Dosimetrically administered nebulized morphine for breathlessness in very severe chronic obstructive pulmonary disease: a randomized, controlled trial

BACKGROUND

Systemic morphine has evidence to support its use for reducing breathlessness in patients with severe chronic obstructive pulmonary disease (COPD). The effectiveness of the nebulized route, however, has not yet been confirmed. Recent studies have shown that opioid receptors are localized within epithelium of human trachea and large bronchi, a target site for a dosimetric nebulizer. The aim of this study was to compare any clinical or statistical differences in breathlessness intensity between nebulized 2.0% morphine and 0,9% NaCl in patients with very severe COPD.

METHODS

The study was a double-blind, controlled, cross-over trial. Participants received morphine or NaCl during two 4-day periods. Sequence of periods was randomized. The primary outcome measure was reduction of breathlessness intensity now by ≥20 mm using a 100 mm visual analogue scale (VAS) at baseline, 15, 30, 60, 120, 180 and 240 min after daily administration, during normal activities.

RESULTS

Ten of 11 patients included completed the study protocol. All patients experienced clinically and statistically significant (p < 0.0001) breathlessness reduction during morphine nebulization. Mean VAS changes for morphine and 0.9% NaCl periods were 25.4 mm (standard deviation (SD): 9.0; median: 23,0; range: 14.0 to 41,5; confidence interval (CI): 95%) and 6.3 mm (SD: 7.8; median: 6.8; range: -11,5 to 19,5; CI: 95%), respectively. No treatment emergent adverse effects were noted.

DISCUSSION

Our study showed superiority of dosimetrically administered nebulized morphine compared to NaCl in reducing breathlessness. This may have been achieved through morphine's direct action on receptors in large airways, although a systemic effect from absorption through the lungs cannot be excluded.

TRIAL REGISTRATION

Retrospectively registered (07.03.2017), ISRCTN14865597.

Respiratory adverse effects of opioids for breathlessness: a systematic review and meta-analysis

Previous studies have shown that opioids can reduce chronic breathlessness in advanced disease. However, physicians remain reluctant to prescribe opioids for these patients, commonly due to fear of respiratory adverse effects. The aim of this study was to systematically review reported respiratory adverse effects of opioids in patients with advanced disease and chronic breathlessness.PubMed, Embase, the Cochrane Central Register of Controlled Trials, CINAHL, ClinicalTrials.gov and the reference lists of relevant systematic reviews were searched. Two independent researchers screened against predefined inclusion criteria and extracted data. Meta-analysis was conducted where possible.We included 63 out of 1990 articles, describing 67 studies. Meta-analysis showed an increase in carbon dioxide tension (0.27 kPa, 95% CI 0.08-0.45 kPa,) and no significant change in oxygen tension and oxygen saturation (both p>0.05). Nonserious respiratory depression (definition variable/not stated) was described in four out of 1064 patients. One cancer patient pretreated with morphine for pain needed temporary respiratory support following nebulised morphine for breathlessness (single case study).We found no evidence of significant or clinically relevant respiratory adverse effects of opioids for chronic breathlessness. Heterogeneity of design and study population, and low study quality are limitations. Larger studies designed to detect respiratory adverse effects are needed.

Managing breathlessness: a palliative care approach

Breathlessness is an important and common symptom globally, affecting patients with a variety of malignant and non-malignant diseases. It causes considerable suffering to patients and also their families, and is a significant cost to healthcare systems. Optimal management of the symptom should therefore be of interest and importance to a wide range of clinicians. Best practice in the management of breathlessness consists of both non-pharmacological and pharmacological interventions as evidenced by recent randomised controlled trials of multidisciplinary breathlessness support services. As well as providing evidence for integration of early palliative care into respiratory services, these revealed that patient distress due to breathlessness can be significantly reduced and better outcomes can be achieved at lower cost than standard care.

Opioids for the palliation of refractory breathlessness in adults with advanced disease and terminal illness

BACKGROUND

Breathlessness is a common and disabling symptom which affects many people with advanced cardiorespiratory disease and cancer. The most effective treatments are aimed at treating the underlying disease. However, this may not always be possible, and symptomatic treatment is often required in addition to maximal disease-directed therapy. Opioids are increasingly being used to treat breathlessness, although their mechanism of action is still not completely known. A few good sized, high quality trials have been conducted in this area.

OBJECTIVES

To determine the effectiveness of opioid drugs in relieving the symptom of breathlessness in people with advanced disease due to malignancy, respiratory or cardiovascular disease, or receiving palliative care for any other disease.

SEARCH METHODS

We performed searches on CENTRAL, MEDLINE, EMBASE, CINAHL, and Web of Science up to 19 October 2015. We handsearched review articles, clinical trial registries, and reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised double-blind controlled trials that compared the use of any opioid drug against placebo or any other intervention for the relief of breathlessness. The intervention was any opioid, given by any route, in any dose.

DATA COLLECTION AND ANALYSIS

We imported studies identified by the search into a reference manager database. We retrieved the full-text version of relevant studies, and two review authors independently extracted data. The primary outcome measure was breathlessness and secondary outcome measures included exercise tolerance, oxygen saturations, adverse events, and mortality. We analysed all studies together and also performed subgroup analyses, by route of administration, type of opioid administered, and cause of breathlessness. Where appropriate, we performed meta-analysis. We assessed the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach and created three 'Summary of findings' tables.

MAIN RESULTS

We included 26 studies with 526 participants. We assessed the studies as being at high or unclear risk of bias overall. We only included randomised controlled trials (RCTs), although the description of randomisation was incomplete in some included studies. We aimed to include double blind RCTs, but two studies were only single blinded. There was inconsistency in the reporting of outcome measures. We analysed the data using a fixed-effect model, and for some outcomes heterogeneity was high. There was a risk of imprecise results due to the low numbers of participants in the included studies. For these reasons we downgraded the quality of the evidence from high to either low or very low.For the primary outcome of breathlessness, the mean change from baseline dyspnoea score was 0.09 points better in the opioids group compared to the placebo group (ranging from a 0.36 point reduction to a 0.19 point increase) (seven RCTs, 117 participants, very low quality evidence). A lower score indicates an improvement in breathlessness. The mean post-treatment dyspnoea score was 0.28 points better in the opioid group compared to the placebo group (ranging from a 0.5 point reduction to a 0.05 point increase) (11 RCTs, 159 participants, low quality evidence).The evidence for the six-minute walk test (6MWT) was conflicting. The total distance in 6MWT was 28 metres (m) better in the opioids group compared to placebo (ranging from 113 m to 58 m) (one RCT, 11 participants, very low quality evidence). However, the change in baseline was 48 m worse in the opioids group (ranging from 36 m to 60 m) (two RCTs, 26 participants, very low quality evidence).The adverse effects reported included drowsiness, nausea and vomiting, and constipation. In those studies, participants were 4.73 times more likely to experience nausea and vomiting compared to placebo, three times more likely to experience constipation, and 2.86 times more likely to experience drowsiness (nine studies, 162 participants, very low quality evidence).Only four studies assessed quality of life, and none demonstrated any significant change.

AUTHORS' CONCLUSIONS

There is some low quality evidence that shows benefit for the use of oral or parenteral opioids to palliate breathlessness, although the number of included participants was small. We found no evidence to support the use of nebulised opioids. Further research with larger numbers of participants, using standardised protocols and with quality of life measures included, is needed.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.