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The American Journal of Gastroenterology Jun 2024Opioids used to manage severe pain in acute pancreatitis might exacerbate the disease through effects on gastrointestinal and immune functions. Methylnaltrexone, a...
OBJECTIVES
Opioids used to manage severe pain in acute pancreatitis might exacerbate the disease through effects on gastrointestinal and immune functions. Methylnaltrexone, a peripherally acting µ-opioid receptor antagonist, may counteract these effects without changing analgesia.
METHODS
This double-blind, randomized, placebo-controlled trial included adult patients with acute pancreatitis and systemic inflammatory response syndrome at four Danish centers. Participants were randomized to receive five days of continuous intravenous methylnaltrexone (0.15mg/kg/day) or placebo added to the standard of care. The primary endpoint was the Pancreatitis Activity Scoring System score after 48 hours of treatment. Main secondary outcomes included pain scores, opioid use, disease severity, and mortality.
RESULTS
In total, 105 patients (54% males) were randomized to methylnaltrexone (n=51) or placebo (n=54). After 48 hours, the Pancreatitis Activity Scoring System score was 134.3 points in the methylnaltrexone group and 130.5 points in the placebo group (difference, 3.8 [95% CI, -40.1 to 47.6]; P=0.87). At 48 hours, we found no differences between groups in pain severity (0.0 [95% CI, -0.8 to 0.9]; P=0.94), pain interference (-0.3 [95% CI, -1.4 to 0.8]; P=0.55), and morphine equivalent doses (6.5 mg [95% CI, -2.1 to 15.2]; P=0.14). Methylnaltrexone also did not affect the risk of severe disease (8% [95% CI, -11 to 28]; P=0.38) and mortality (6% [95% CI, -1 to 12]; P=0.11). The medication was well-tolerated.
CONCLUSIONS
Methylnaltrexone treatment did not achieve superiority over placebo for reducing the severity of acute pancreatitis.
PubMed: 38916223
DOI: 10.14309/ajg.0000000000002904 -
The American Journal of Gastroenterology Jun 2024Opioid receptors are found throughout the gastrointestinal tract, including the large intestine. Many patients treated with opioids experience opioid-induced...
Opioid receptors are found throughout the gastrointestinal tract, including the large intestine. Many patients treated with opioids experience opioid-induced constipation. Laxatives are not effective in most patients, and in those who do initially respond, the efficacy of laxatives generally diminishes over time. Additionally, opioid-induced constipation does not spontaneously resolve for most patients. However, complications of opioids extend far beyond simply slowing gastrointestinal transit. Opioid use can affect intestinal permeability through a variety of mechanisms. Toll-like receptors (TLRs) are a crucial component of innate immunity and are tightly regulated within the gut epithelium. Pathologic µ-opioid receptor and TLR signaling, resulting from chronic opioid exposure, disrupts intestinal permeability leading to potentially harmful bacterial translocation, elevated levels of bacterial toxins, immune activation, and increased cytokine production. Peripherally active µ-opioid receptor antagonists, including methylnaltrexone, are effective at treating opioid-induced constipation. Benefits extend beyond simply blocking the µ-opioid receptor; these agents also act to ameliorate opioid-induced disrupted intestinal permeability. In this review we briefly describe the physiology of the gastrointestinal epithelial border and discuss the impact of opioids on gastrointestinal function. Finally, we consider the use of peripherally active µ-opioid receptor antagonists to treat disrupted intestinal permeability resulting from opioid use and discuss the potential for improved morbidity and mortality in patients treated with methylnaltrexone for opioid-induced bowel disorders.
PubMed: 38870087
DOI: 10.14309/ajg.0000000000002887 -
The Journal of Pediatric Pharmacology... Jun 2024Constipation is a common adverse event of opioid use that is often difficult to treat. Methylnaltrexone is a therapeutic option for opioid-induced constipation (OIC)...
OBJECTIVES
Constipation is a common adverse event of opioid use that is often difficult to treat. Methylnaltrexone is a therapeutic option for opioid-induced constipation (OIC) approved for oral and subcutaneous use in adults. These administration routes are not always feasible in the pediatric population. The primary objective of this research was to quantify the response rate of methylnaltrexone in pediatric patients when it was administered via the intravenous (IV) route.
METHODS
This retrospective study evaluated patients ages <18 years who received IV methylnaltrexone between January 1, 2013, and June 30, 2020, for OIC. Efficacy was evaluated through documentation of bowel evacuation within 4 hours of methylnaltrexone administration. Adverse events observed within 24 hours of administration were attributed to methylnaltrexone.
RESULTS
Methylnaltrexone was administered to 134 unique patients during the study period. Of these, 46 met exclusion criteria, resulting in 88 patients being included in the study. Patients with an underlying hematology/oncology diagnosis consisted of 77% of the study population, and 23% of patients had an -underlying medical/surgical diagnosis. The response rate to IV methylnaltrexone was 25% (CI, 16-34).
CONCLUSIONS
The results of this retrospective chart review demonstrate the potential role of IV methylnaltrexone in the pediatric population. Despite the overall lower response rate relative to that reported in adults, IV methylnaltrexone possesses a unique mechanism of action that may serve as an alternative treatment option for patients unable to use the oral and subcutaneous administration routes. There were no significant adverse events seen in the study.
PubMed: 38863861
DOI: 10.5863/1551-6776-29.3.292 -
Journal of Neurogastroenterology and... Apr 2024Daily use of opioid analgesics has significantly increased in recent years due to an increasing prevalence of conditions associated with chronic pain. Opioid-induced... (Review)
Review
Daily use of opioid analgesics has significantly increased in recent years due to an increasing prevalence of conditions associated with chronic pain. Opioid-induced constipation (OIC) is one of the most common, under-recognized, and under-treated side effects of opioid analgesics. OIC significantly reduces the quality of life by causing psychological distress, lowering work productivity, and increasing access to healthcare facilities. The economic and social burden of OIC led to the development of precise strategies for daily clinical practice. Key aspects are the prevention of constipation through adequate water intake and fiber support, avoidance of sedentariness, and early recognition and treatment of cofactors that could worsen constipation. Recommended first-line therapy includes osmotic (preferably polyethylene glycol) and stimulant laxatives. Peripherally acting μ-opioid receptor antagonists, such as methylnaltrexone, naloxegol, or naldemedine, should be used in patients that have not responded to the first-line treatments. The bowel functional index is the main tool for assessing the severity of OIC and for monitoring the response. The paper discusses the recent literature on the pathophysiology, clinical evaluation, and management of OIC and provides a pragmatic approach for its assessment and treatment.
PubMed: 38576366
DOI: 10.5056/jnm23144 -
Cancer Treatment Reviews Apr 2024Cancer-related pain often requires opioid treatment with opioid-induced constipation (OIC) as its most frequent gastrointestinal side-effect. Both for prevention and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Cancer-related pain often requires opioid treatment with opioid-induced constipation (OIC) as its most frequent gastrointestinal side-effect. Both for prevention and treatment of OIC osmotic (e.g. polyethylene glycol) and stimulant (e.g. bisacodyl) laxatives are widely used. Newer drugs such as the peripherally acting µ-opioid receptor antagonists (PAMORAs) and naloxone in a fixed combination with oxycodone have become available for the management of OIC. This systematic review and meta-analysis aims to give an overview of the scientific evidence on pharmacological strategies for the prevention and treatment of OIC in cancer patients.
METHODS
A systematic search in PubMed, Embase, Web of Science and the Cochrane Library was completed from inception up to 22 October 2022. Randomized and non-randomized studies were systematically selected. Bowel function and adverse drug events were assessed.
RESULTS
Twenty trials (prevention: five RCTs and three cohort studies; treatment: ten RCTs and two comparative cohort studies) were included in the review. Regarding the prevention of OIC, three RCTs compared laxatives with other laxatives, finding no clear differences in effectivity of the laxatives used. One cohort study showed a significant benefit of magnesium oxide compared with no laxative. One RCT found a significant benefit for the PAMORA naldemedine compared with magnesium oxide. Preventive use of oxycodone/naloxone did not show a significant difference in two out of three other studies compared to oxycodone or fentanyl. A meta-analysis was not possible. Regarding the treatment of OIC, two RCTs compared laxatives, of which one RCT found that polyethylene glycol was significantly more effective than sennosides. Seven studies compared an opioid antagonist (naloxone, methylnaltrexone or naldemedine) with placebo and three studies compared different dosages of opioid antagonists. These studies with opioid antagonists were used for the meta-analysis. Oxycodone/naloxone showed a significant improvement in Bowel Function Index compared to oxycodone with laxatives (MD -13.68; 95 % CI -18.38 to -8.98; I = 58 %). Adverse drug event rates were similar amongst both groups, except for nausea in favour of oxycodone/naloxone (RR 0.51; 95 % CI 0.31-0.83; I = 0 %). Naldemedine (NAL) and methylnaltrexone (MNTX) demonstrated significantly higher response rates compared to placebo (NAL: RR 2.07, 95 % CI 1.64-2.61, I = 0 %; MNTX: RR 3.83, 95 % CI 2.81-5.22, I = 0 %). With regard to adverse events, abdominal pain was more present in treatment with methylnaltrexone and diarrhea was significantly more present in treatment with naldemedine. Different dosages of methylnaltrexone were not significantly different with regard to both efficacy and adverse drug event rates.
CONCLUSIONS
Magnesium oxide and naldemedine are most likely effective for prevention of OIC in cancer patients. Naloxone in a fixed combination with oxycodone, naldemedine and methylnaltrexone effectively treat OIC in cancer patients with acceptable adverse events. However, their effect has not been compared to standard (osmotic and stimulant) laxatives. More studies comparing standard laxatives with each other and with opioid antagonists are necessary before recommendations for clinical practice can be made.
Topics: Humans; Laxatives; Analgesics, Opioid; Narcotic Antagonists; Constipation; Oxycodone; Opioid-Induced Constipation; Magnesium Oxide; Cohort Studies; Naloxone; Polyethylene Glycols; Neoplasms; Drug-Related Side Effects and Adverse Reactions; Quaternary Ammonium Compounds; Naltrexone
PubMed: 38452708
DOI: 10.1016/j.ctrv.2024.102704 -
Palliative Medicine Reports 2024In addition to the more well-known adverse effects of opioids, such as constipation, mounting evidence supports underlying immunosuppressive effects as well.
BACKGROUND
In addition to the more well-known adverse effects of opioids, such as constipation, mounting evidence supports underlying immunosuppressive effects as well.
METHODS
In this study, we provide a narrative review of preclinical and clinical evidence of opioid suppression of the immune system as well as possible considerations for therapies.
RESULTS
and animal studies have shown clear effects of opioids on inflammatory cytokine expression, immune cell activity, and pathogen susceptibility. Observational data in humans have so far supported preclinical findings, with multiple reports of increased rates of infections in various settings of opioid use. However, the extent to which this risk is due to the impact of opioids on the immune system compared with other risk factors associated with opioid use remains uncertain. Considering the data showing immunosuppression and increased risk of infection with opioid use, measures are needed to mitigate this risk in patients who require ongoing treatment with opioids. In preclinical studies, administration of opioid receptor antagonists blocked the immunomodulatory effects of opioids.
CONCLUSIONS
As selective antagonists of peripheral opioid receptors, peripherally acting mu-opioid receptor (MOR) antagonists may be able to protect against immune impairment while still allowing for opioid analgesia. Future research is warranted to further investigate the relationship between opioids and infection risk as well as the potential application of peripherally acting MOR antagonists to counteract these risks.
PubMed: 38435086
DOI: 10.1089/pmr.2023.0049 -
Journal of Pain and Symptom Management Apr 2024Constipation is a common problem among patients with cancer. By some accounts, about 60% of cancer patients experience constipation. There is limited empirical evidence... (Meta-Analysis)
Meta-Analysis Review
CONTEXT
Constipation is a common problem among patients with cancer. By some accounts, about 60% of cancer patients experience constipation. There is limited empirical evidence of the clinical effectiveness of pharmacologic agents in opioid-induced constipation in advanced diseases.
OBJECTIVES
We sought to quantitatively summarize the therapeutic effectiveness of the pharmacologic means of managing opioid-induced constipation.
METHODS
Randomized control trials (RCTs) identified from medical literature databases that reported quantitative measures of the effect of pharmacotherapeutic agents to treat opioid induced constipation in patients with cancers and other advanced illnesses were included in this study. A conventional random effects meta-analysis was conducted including >3 trials with the same exposure and outcome assessed, and a network-meta-analysis was conducted for all placebo-controlled trials.
RESULTS
Eighteen studies that examined the effect of various pharmacotherapeutic agents were included. The medications were Methylnatrexone (N = 5), Naldemedine (N = 5), other conventional agents (N = 4) and herbal medicines (N = 4). In conventional meta-analysis, methylnaltrexone increased the proportion achieving rescue-free laxation by 2.68 fold (95% CI: 1.34, 5.37; P = 0.0054) within 4 hours of the administration compared to placebo. In network meta-analysis, the pooled RR of the pharmacotherapeutic agents on rescue-free bowel movements as 2.26 (95% CI: 1.52, 3.36) for methylnaltrexone, 1.58 (95% CI: 0.94, 2.66) for naldemedine, and 0.74 (95% CI: 0.45, 1.23) for polyethylene glycol, compared to placebo.
CONCLUSION
Methylnatrexone and Naldemedine have currently shown promise in randomized trials concerning opioid-induced constipation in cancer and advanced illness. It is imperative that future research ascertain not just the relative therapeutic efficacy but also the cost-benefit analyses of these newer regimens with more commonly used and accessible laxatives.
Topics: Humans; Opioid-Induced Constipation; Narcotic Antagonists; Analgesics, Opioid; Naltrexone; Constipation; Laxatives; Neoplasms; Randomized Controlled Trials as Topic; Quaternary Ammonium Compounds
PubMed: 38092261
DOI: 10.1016/j.jpainsymman.2023.12.010 -
The Annals of Pharmacotherapy Jul 2024Constipation impacts 58% to 83% of critically ill patients and is associated with increased time on mechanical ventilation, delirium, and increased length of stay (LOS)... (Comparative Study)
Comparative Study
BACKGROUND
Constipation impacts 58% to 83% of critically ill patients and is associated with increased time on mechanical ventilation, delirium, and increased length of stay (LOS) in the intensive care unit (ICU).
OBJECTIVE
The purpose of this study was to evaluate the efficacy of enteral naloxegol (NGL) versus subcutaneous methylnaltrexone (MNTX) for the management of opioid-induced constipation (OIC) in critically ill patients.
METHODS
A retrospective analysis was conducted on adult patients admitted to the ICU who received a parenteral opioid infusion for at least 4 hours and experienced no bowel movement (BM) within the 48-hour period preceding the administration of NGL or MNTX. The primary outcome was time to first BM from the start of NGL or MNTX therapy. Secondary outcomes included number of BMs 72 hours following NGL or MNTX administration, ICU LOS, and cost-effectiveness.
RESULTS
After exclusion criteria were applied, 110 and 51 patients were included in the NGL and MNTX groups, respectively. With a 10% noninferiority margin, NGL was noninferior to MNTX (Wald statistic = 1.67; = 0.047). Median time to first BM was 23.7 hours for NGL and 18.3 hours for MNTX patients. Median LOS was 14 days (NGL) and 12 days (MNTX), and the average number of BMs in 72 hours was 3.9 for NGL and 3.8 for MNTX. Using wholesale acquisition cost (WAC), the cost per BM for NGL and MNTX was $21.74 and $170.00, respectively.
CONCLUSION AND RELEVANCE
This study determined that NGL and MNTX had similar time to BM. NGL appears to be a safe and effective alternative with cost-saving potential in treating OIC in critically ill patients.
Topics: Humans; Male; Naltrexone; Female; Critical Illness; Middle Aged; Retrospective Studies; Polyethylene Glycols; Narcotic Antagonists; Quaternary Ammonium Compounds; Morphinans; Analgesics, Opioid; Aged; Opioid-Induced Constipation; Adult; Length of Stay; Intensive Care Units; Constipation
PubMed: 37881915
DOI: 10.1177/10600280231205023 -
Journal of Pain Research 2023We evaluated the impact of baseline patient characteristics on safety and efficacy of methylnaltrexone, a peripherally acting µ-opioid receptor antagonist, in patients...
PURPOSE
We evaluated the impact of baseline patient characteristics on safety and efficacy of methylnaltrexone, a peripherally acting µ-opioid receptor antagonist, in patients with advanced illness with opioid-induced constipation (OIC).
PATIENTS AND METHODS
This analysis pooled data from 2 randomized, double-blind, placebo-controlled studies (study 302: NCT00402038; study 4000: NCT00672477) in patients with advanced illness, including cancer, and OIC. Patients were randomized to receive subcutaneous methylnaltrexone (study 302: 0.15 mg/kg; study 4000: 8 or 12 mg based on weight) or placebo every other day for 2 weeks. The proportions of patients achieving rescue-free laxation within 4 or 24 hours after the first dose of study drug were assessed in patient subgroups stratified by baseline age, Eastern Cooperative Oncology Group (ECOG) performance status, cancer status, laxative type, and opioid requirement. Treatment-emergent adverse events (TEAEs) were evaluated.
RESULTS
Overall, 363 patients were included in this analysis (methylnaltrexone, 178; placebo, 185). Mean (SD) age was 66.3 (13.7) years and 48.5% were men overall. A significantly greater proportion of patients receiving methylnaltrexone versus placebo achieved rescue-free laxation within 4 hours (111/178 [62.4%] vs 31/185 [16.8%]; <0.0001) and 24 hours (135/178 [75.8%] vs 81/185 [43.8%]; <0.0001) of the first dose. These trends were consistent across all subgroups. Most patients experienced ≥1 TEAE in the overall population (methylnaltrexone, 82.1%; placebo, 76.2%), which remained consistent when stratified by baseline characteristics. More than half of TEAEs were gastrointestinal in nature. Abdominal pain was more common in patients receiving methylnaltrexone than placebo across baseline characteristic subgroups.
CONCLUSION
Methylnaltrexone treatment was superior to placebo in achieving rescue-free laxation within 4 and 24 hours after the first dose, irrespective of patients' cancer status, baseline ECOG performance status, or baseline opioid or laxative use. The methylnaltrexone safety profile remained consistent across baseline characteristic subgroups.
PubMed: 37881233
DOI: 10.2147/JPR.S416307