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Journal of the American Association For... May 2023Opioids are an integral component of pain management for nonhuman primates. These potent analgesics also adverse gastrointestinal (GI) effects that include constipation,...
Opioids are an integral component of pain management for nonhuman primates. These potent analgesics also adverse gastrointestinal (GI) effects that include constipation, bloating, and delayed gastric emptying. Methylnaltrexone bromide (MNTX) is a selective, peripherally acting μ- and κ-opioid receptor antagonist that can be used to mitigate the GI effects associated with opioid administration. Unlike naltrexone, a similar drug in this class, MNTX possesses an N-methyl-quaternary amine group that prevents it from crossing the blood brain barrier. This blockage allows inhibition of peripheral GI opioid receptors without affecting opioid-mediated analgesia in the central nervous system. We conducted a pharmacokinetic analysis of MNTX in serum and CSF of 6 healthy juvenile male rhesus macaques after subcutaneous administration of a 0.15-mg/kg dose. We hypothesized that the macaques would demonstrate a T of 0.5 h, similar to that of humans, and that no MNTX would be detected in the CSF. This treatment resulted in a peak serum concentration of 114 ± 44 ng/mL at 0.25 ± 0.00 h; peak CSF at concentrations were 0.34 ± 0.07 ng/mL at the T. These data show that subcutaneous administration of MNTX to rhesus macaques may block peripheral adverse effects of opioids without interfering with their central analgesic effects.
Topics: Humans; Male; Animals; Naltrexone; Macaca mulatta; Narcotic Antagonists; Analgesics, Opioid; Quaternary Ammonium Compounds
PubMed: 37080736
DOI: 10.30802/AALAS-JAALAS-22-000111 -
Current Therapeutic Research, Clinical... 2023Opioid-induced constipation (OIC) may increase the risk of fecal impaction and mortality in patients with advanced illness. Methylnaltrexone (MNTX) is efficacious for...
BACKGROUND
Opioid-induced constipation (OIC) may increase the risk of fecal impaction and mortality in patients with advanced illness. Methylnaltrexone (MNTX) is efficacious for OIC.
OBJECTIVE
The purpose of this analysis was to evaluate cumulative rescue-free laxation response with repeat MNTX dosing in patients with advanced illness who were refractory to current laxative regimens and to assess the influence, if any, of poor functional status on response to MNTX treatment.
METHODS
This analysis included pooled data from patients with advanced illness and established OIC who were on a stable opioid regimen in a pivotal, randomized, placebo (PBO)-controlled clinical trial (study 302 [NCT00402038]) or a randomized, PBO-controlled Food and Drug Administration-required postmarketing study (study 4000 [NCT00672477]). Patients in study 302 received subcutaneous MNTX 0.15 mg/kg or PBO every other day, whereas those in study 4000 received MNTX 8 mg (body weight ≥38 to <62 kg), MNTX 12 mg (body weight ≥62 kg), or PBO every other day. Outcomes included cumulative rescue-free laxation rates at 4- and 24-hours postdose for the first 3 doses of study drug and time to rescue-free laxation. To assess if functional status influenced treatment outcomes, we performed a secondary analysis on the outcomes stratified by baseline World Health Organization/Eastern Cooperative Oncology Group performance status, pain scores, and safety.
RESULTS
One hundred eighty-five patients received PBO and 179 patients received MNTX. The median age was 66.0 years, 51.5% were women, 56.5% had a baseline World Health Organization/Eastern Cooperative Oncology Group performance status score >2, and 63.4% had a primary diagnosis of cancer. Cumulative rescue-free laxation rates were significantly higher with MNTX than PBO 4- and 24-hours after doses 1, 2, and 3 ( < 0.0001), and between-treatment comparisons remained significant ( < 0.0001) regardless of performance status. The estimated time to first rescue-free laxation was shorter for patients receiving MNTX versus PBO. No new safety signals were identified.
CONCLUSIONS
Repeated use of MNTX represents a safe and effective treatment for OIC in patients with advanced illness regardless of baseline performance status. ClinicalTrials.gov identifier: NCT00672477. (. 2023; 84:XXX-XXX)© 2023 Elsevier HS Journals, Inc.
PubMed: 36875317
DOI: 10.1016/j.curtheres.2023.100694 -
Journal of Pain Research 2023To evaluate the efficacy and safety of subcutaneous (SC) methylnaltrexone for opioid-induced constipation (OIC) in patients with and without active cancer.
Subcutaneous Methylnaltrexone as Treatment for Opioid-Induced Constipation in Patients with Advanced Cancer and Noncancer Illnesses: A Post Hoc Analysis of Two Clinical Trials.
PURPOSE
To evaluate the efficacy and safety of subcutaneous (SC) methylnaltrexone for opioid-induced constipation (OIC) in patients with and without active cancer.
PATIENTS AND METHODS
We analyzed two randomized, double-blind, placebo-controlled, Phase 3/4 trials (NCT00402038, NCT00672477). Patients received SC methylnaltrexone (study 302, 0.15 mg/kg; study 4000, 8 mg or 12 mg based on body weight) or placebo every other day for 2 weeks. Patients were stratified by cancer status. Primary efficacy endpoints included proportion of patients achieving rescue-free laxation (RFL); secondary endpoints included time to RFL, pain intensity scores, and safety/tolerability. Trial results were evaluated separately.
RESULTS
The safety population (patients receiving ≥1 study drug dose) included 364 patients (study 302, n=134; study 4000, n=230). Study 302 had 78 patients with active cancer (methylnaltrexone, n=37; placebo, n=41) and 56 without cancer (methylnaltrexone, n=26; placebo, n=30); study 4000 had 152 patients with active cancer (methylnaltrexone, n=79; placebo, n=73) and 78 without cancer (methylnaltrexone, n=37; placebo, n=41). A significantly greater proportion of patients treated with methylnaltrexone achieved a laxation response within 4 hours after at least 2 of the first 4 doses versus placebo, dosed by body weight (cancer, 54.1% [methylnaltrexone] vs 7.3% [placebo], <0.0001; noncancer, 48.0% vs 10.0%; <0.005) or given as a weight-adjusted fixed dose (cancer, 59.5% vs 6.8%; noncancer, 70.3% vs 14.6%; <0.0001 each). With fixed-dose methylnaltrexone, average time to RFL for patients with and without cancer was <1 hour of the first dose; with methylnaltrexone dosed by body weight, the first RFL occurred in <4 and <7 hours of treatment in patients with and without cancer, respectively. No significant differences were found in pain scores. SC methylnaltrexone was well tolerated at all doses in all patient cohorts.
CONCLUSION
SC methylnaltrexone was efficacious in inducing rapid RFL and safe among patients with and without active cancer suffering from OIC.
PubMed: 36798078
DOI: 10.2147/JPR.S366460 -
The Cochrane Database of Systematic... Sep 2022Opioid-induced bowel dysfunction (OIBD) is characterised by constipation, incomplete evacuation, bloating, and gastric reflux. It is one of the major adverse events... (Review)
Review
BACKGROUND
Opioid-induced bowel dysfunction (OIBD) is characterised by constipation, incomplete evacuation, bloating, and gastric reflux. It is one of the major adverse events (AEs) of treatment for pain in cancer and palliative care, resulting in increased morbidity and reduced quality of life. This review is a partial update of a 2008 review, and critiques as previous update (2018) trials only for people with cancer and people receiving palliative care.
OBJECTIVES
To assess for OIBD in people with cancer and people receiving palliative care the effectiveness and safety of mu-opioid antagonists (MOAs) versus different doses of MOAs, alternative pharmacological/non-pharmacological interventions, placebo, or no treatment.
SEARCH METHODS
We searched CENTRAL, MEDLINE, Embase, CINAHL, and Web of Science (December 2021), clinical trial registries and regulatory websites. We sought contact with MOA manufacturers for further data.
SELECTION CRITERIA
Randomised controlled trials (RCTs) assessing the effectiveness and safety of MOAs for OIBD in people with cancer and people at a palliative stage irrespective of the type of terminal disease.
DATA COLLECTION AND ANALYSIS
Two review authors assessed risk of bias and extracted data. The appropriateness of combining data from the trials depended upon sufficient homogeneity across trials. Our primary outcomes were laxation response, effect on analgesia, and AEs. We assessed the certainty of evidence using GRADE and created summary of findings tables.
MAIN RESULTS
We included 10 studies (two new trials) randomising in-total 1343 adults with cancer irrespective of stage, or at palliative care stage of any disease. The MOAs were oral naldemedine and naloxone (alone or in combination with oxycodone), and subcutaneous methylnaltrexone. The trials compared MOAs with placebo, MOAs at different doses, or in combination with other drugs. Two trials of naldemedine and three of naloxone with oxycodone were in people with cancer irrespective of disease stage. The trial on naloxone alone was in people with advanced cancer. Four trials on methylnaltrexone were in palliative care where most participants had advanced cancer. All trials were vulnerable to biases; most commonly, blinding of the outcome assessor was not reported. Oral naldemedine versus placebo Risk (i.e. chance) of spontaneous laxations in the medium term (over two weeks) for naldemedine was over threefold greater risk ratio (RR) 2.00, 95% confidence interval (CI) 1.59 to 2.52, 2 trials, 418 participants, I² = 0%. Number needed to treat for an additional beneficial outcome (NNTB) 3, 95% CI 3 to 4; moderate-certainty evidence). Earlier risk of spontaneous laxations and patient assessment of bowel change was not reported. Very low-certainty evidence showed naldemedine had little to no effect on opioid withdrawal symptoms. There was little to no difference in the risk of serious (non-fatal) AEs (RR 3.34, 95% CI 0.85 to 13.15: low-certainty evidence). Over double the risk of AEs (non-serious) reported with naldemedine (moderate-certainty evidence). Low-dose oral naldemedine versus higher dose Risk of spontaneous laxations was lower for the lower dose (medium term, 0.1 mg versus 0.4 mg: RR 0.69, 95% CI 0.53 to 0.89, 1 trial, 111 participants (low-certainty evidence)). Earlier risk of spontaneous laxations and patient assessment of bowel change not reported. Low-certainty evidence showed little to no difference on opioid withdrawal symptoms (0.1 mg versus 0.4 mg mean difference (MD) -0.30, 95% CI -0.85 to 0.25), and occurrences of serious AEs (0.1 mg versus 0.4 mg RR 0.25, 95% CI 0.03 to 2.17). Low-certainty evidence showed little to no difference on non-serious AEs. Oral naloxone versus placebo Risk of spontaneous laxations and AEs not reported. Little to no difference in pain intensity (very low-certainty evidence). Full data not given. The trial reported that no serious AEs occurred. Oral naloxone + oxycodone versus oxycodone Risk of spontaneous laxations within 24 hours and in the medium term not reported. Low-certainty evidence showed naloxone with oxycodone reduced the risk of opioid withdrawal symptoms. There was little to no difference in the risk of serious (non-fatal) AEs (RR 0.68, 95% CI 0.44 to 1.06), 3 trials, 362 participants, I² = 55%: very low-certainty evidence). There was little to no difference in risk of AEs (low-certainty evidence). Subcutaneous methylnaltrexone versus placebo Risk of spontaneous laxations within 24 hours with methylnaltrexone was fourfold greater than placebo (RR 2.97, 95% CI 2.13 to 4.13. 2 trials, 287 participants, I² = 31%. NNTB 3, 95% CI 2 to 3; low-certainty evidence). Risk of spontaneous laxations in the medium term was over tenfold greater with methylnaltrexone (RR 8.15, 95% CI 4.76 to 13.95, 2 trials, 305 participants, I² = 47%. NNTB 2, 95% CI 2 to 2; moderate-certainty evidence). Low-certainty evidence showed methylnaltrexone reduced the risk of opioid withdrawal symptoms, and did not increase risk of a serious AE (RR 0.59, 95% CI 0.38 to 0.93. I² = 0%; 2 trials, 364 participants). The risk of AEs was higher for methylnaltrexone (low-certainty evidence). Lower-dose subcutaneous methylnaltrexone versus higher dose There was little to no difference in risk of spontaneous laxations in the medium-term (1 mg versus 5 mg or greater: RR 2.91, 95% CI 0.82 to 10.39; 1 trial, 26 participants very low-certainty evidence), or in patient assessment of improvement in bowel status (RR 0.98, 95% CI 0.71 to 1.35, 1 trial, 102 participants; low-certainty evidence). Medium-term assessment of spontaneous laxations and serious AEs not reported. There was little to no difference in symptoms of opioid withdrawal (MD -0.25, 95% CI -0.84 to 0.34, 1 trial, 102 participants) or occurrence of AEs (low-certainty evidence).
AUTHORS' CONCLUSIONS
This update's findings for naldemedine and naloxone with oxycodone have been strengthened with two new trials, but conclusions have not changed. Moderate-certainty evidence for oral naldemedine on risk of spontaneous laxations and non-serious AEs suggests in people with cancer that naldemedine may improve bowel function over two weeks and increase the risk of AEs. There was low-certainty evidence on serious AEs. Moderate-certainty evidence for methylnaltrexone on spontaneous laxations over two weeks suggests subcutaneous methylnaltrexone may improve bowel function in people receiving palliative care, but certainty of evidence for AEs was low. More trials are needed, more evaluation of AEs, outcomes patients rate as important, and in children.
Topics: Adult; Analgesics, Opioid; Child; Humans; Naloxone; Naltrexone; Narcotic Antagonists; Neoplasms; Opioid-Induced Constipation; Oxycodone; Palliative Care; Quaternary Ammonium Compounds; Substance Withdrawal Syndrome
PubMed: 36106667
DOI: 10.1002/14651858.CD006332.pub4 -
Pain Medicine (Malden, Mass.) Mar 2023Preclinical and clinical studies suggest that activation of the µ-opioid receptor may reduce overall survival and increase the risk for all-cause mortality in patients... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
Preclinical and clinical studies suggest that activation of the µ-opioid receptor may reduce overall survival and increase the risk for all-cause mortality in patients with cancer and noncancer pain. Methylnaltrexone, a selective, peripherally acting µ-opioid receptor antagonist, has demonstrated efficacy for the treatment of opioid-induced constipation. This retrospective analysis of 12 randomized, double-blind, placebo-controlled studies of methylnaltrexone evaluated the treatment of opioid-induced bowel disorders in patients with advanced illness or noncancer pain.
METHODS
The risk of all-cause mortality within 30 days after the last dose of study medication during the double-blind phase was compared between methylnaltrexone and placebo groups. The data were further stratified by cancer vs noncancer, age, gender, and acute vs chronic diagnoses.
RESULTS
Pooled data included 2,526 methylnaltrexone-treated patients of which 33 died, and 1,192 placebo-treated patients of which 35 died. The mortality rate was 17.8 deaths/100 person-years of exposure in the methylnaltrexone group and 49.5 deaths/100 person-years of exposure for the placebo group. The all-cause mortality risk was significantly lower among patients receiving methylnaltrexone compared with placebo (hazard ratio: 0.399, 95% confidence interval: 0.25, 0.64; P = .0002), corresponding to a 60% risk reduction. Significant risk reductions were observed for those receiving methylnaltrexone who had cancer or chronic diagnoses. Methylnaltrexone-treated patients had a significantly reduced mortality risk compared with placebo regardless of age or gender.
CONCLUSIONS
Methylnaltrexone reduced all-cause mortality vs placebo treatment across multiple trials, suggesting methylnaltrexone may confer survival benefits in patients with opioid-induced bowel disorders taking opioids for cancer-related or chronic noncancer pain.
Topics: Humans; Analgesics, Opioid; Retrospective Studies; Constipation; Chronic Pain; Naltrexone; Narcotic Antagonists; Double-Blind Method; Randomized Controlled Trials as Topic
PubMed: 36102822
DOI: 10.1093/pm/pnac136 -
Current Oncology Reports Oct 2022Antagonists of mu-opioid receptor role in cancer progression remains to be elucidated. The objective of this review was to summarize the available evidence on... (Review)
Review
PURPOSE OF REVIEW
Antagonists of mu-opioid receptor role in cancer progression remains to be elucidated. The objective of this review was to summarize the available evidence on antagonists of mu-opioid receptor effect on tumor progression and prognosis in different types of cancers and an evaluation of the available findings on their mechanism of action.
RECENT FINDINGS
We have found studies related to methylnaltrexone (MNTX) and naltrexone (NTX) usage in cancer outcomes-related setting. We found consistent preclinical evidence of a potential action of MNTX and NTX on cancer growth and spread mediated mainly by effect on the opioid growth factor receptor (OGFr) axis, which results in depressed cell replication. However, clinical results are scarce and limited to poor-quality evidence. Further high-quality studies are warranted to study antagonists of mu-opioid receptor role as a therapeutic option in different types of cancer, especially in patients where the classical treatment causes unacceptable side effects.
Topics: Cell Proliferation; Humans; Naltrexone; Narcotic Antagonists; Neoplasms; Quaternary Ammonium Compounds; Receptors, Opioid
PubMed: 35648340
DOI: 10.1007/s11912-022-01295-z -
The Journal of Pediatric Pharmacology... 2022To evaluate the association between methylnaltrexone and urine output (UOP) in critically ill children with opioid-associated urinary retention.
OBJECTIVE
To evaluate the association between methylnaltrexone and urine output (UOP) in critically ill children with opioid-associated urinary retention.
METHODS
This retrospective study included patients admitted to the pediatric intensive care unit between December 1, 2019, and November 30, 2020, who received methylnaltrexone for opioid-associated oliguria (spontaneous UOP below 1 mL/kg/hr and at least 1 dose of an opioid within the preceding 6 hours).
RESULTS
Twenty-five patients (median age = 5.5 years, IQR 1.7-16.4; median weight = 19 kg, IQR 9-45) were included. Mean methylnaltrexone dose was 0.15 ± 0.006 mg/kg. A statistically significant increase in UOP from baseline to 6 hours following methylnaltrexone was observed (p = 0.001), but not all patients responded. Fourteen patients (56%) had no UOP following methylnaltrexone administration, while 11 (44%) demonstrated a robust increase (median = 0 mL/kg/hr at baseline [IQR 0-0] to 1.96 mL/kg/hr [IQR 1.08-2.22; p = 0.001]) within 6 hours following methylnaltrexone administration. Younger patients responded better than older patients (responder age = 2.5 years [IQR 0.8-7]) versus 11.4 years [IQR 1.75-17.5] for non-responders) (p = 0.04). Both intravenous (IV) and subcutaneous (SQ) routes were associated with an increase in UOP (IV, p = 0.04; SQ, p = 0.02). The effect persisted for up to 24 hours after administration. Sixty-four percent of patients required urinary catheter placement. Pain scores (averaged 6 hours before and after methylnaltrexone) remained unchanged (p = 0.44).
CONCLUSIONS
Methylnaltrexone may increase spontaneous UOP in some children with opioid-associated urinary retention, but urinary catheterization rates remain high.
PubMed: 35558358
DOI: 10.5863/1551-6776-27.4.373 -
Advances in Therapy May 2022Opioid-induced constipation (OIC) prescription medications (OIC-Rx) like methylnaltrexone subcutaneous (SC) have shown efficacy in treating OIC in the emergency...
INTRODUCTION
Opioid-induced constipation (OIC) prescription medications (OIC-Rx) like methylnaltrexone subcutaneous (SC) have shown efficacy in treating OIC in the emergency department (ED). This study aimed to describe and compare healthcare resource utilization (HRU) and healthcare costs in ED patients with OIC receiving OIC-Rx versus those not receiving OIC-Rx.
METHODS
Adult patients with OIC during an ED encounter were identified from a hospital-based ED encounters database (2016-2019) and classified on the basis of receipt of OIC-Rx (OIC-Rx versus No OIC-Rx cohorts). Entropy balancing was used to reweight characteristics of the two cohorts. HRU and healthcare costs were measured and compared during the ED encounter and 30-day post-discharge period.
RESULTS
Among 11,135 patients in the OIC-Rx cohort (21,474 in the No OIC-Rx cohort), 93% received methylnaltrexone SC. Patients in the OIC-Rx cohort had 0.7 fewer inpatient days per OIC ED encounter and 64% decreased odds of being hospitalized versus the No OIC-Rx cohort (both p < 0.001). During the post-discharge period, the OIC-Rx cohort had 35% decreased odds of any re-encounter (p < 0.001). The OIC-Rx cohort had a $732 reduction in costs per OIC ED encounter versus the No OIC-Rx cohort (p < 0.001), driven by larger hospitals and patients with Medicare or Commercial insurance. During the post-discharge period, the OIC-Rx cohort had a $421 reduction in costs associated with any re-encounter versus the No OIC-Rx cohort (p = 0.004).
CONCLUSION
Patients receiving OIC-Rx in the ED had decreased odds of being hospitalized and fewer re-encounters in the 30-day post-discharge period versus patients who did not receive OIC-Rx, resulting in cost savings for insurance agencies and healthcare providers.
Topics: Adult; Aftercare; Aged; Analgesics, Opioid; Constipation; Emergency Service, Hospital; Humans; Medicare; Opioid-Induced Constipation; Patient Discharge; United States
PubMed: 35298784
DOI: 10.1007/s12325-022-02090-9 -
Journal of Medicinal Chemistry Mar 2022Opioid-induced constipation (OIC) is a common adverse effect of opioid analgesics. Peripherally acting μ opioid receptor antagonists (PAMORAs) can be applied in the...
Opioid-induced constipation (OIC) is a common adverse effect of opioid analgesics. Peripherally acting μ opioid receptor antagonists (PAMORAs) can be applied in the treatment of OIC without compromising the analgesic effects. NAP, a 6β-N-4-pyridyl-substituted naltrexamine derivative, was previously identified as a potent and selective MOR antagonist mainly acting peripherally but with some CNS effects. Herein, we introduced a highly polar aromatic moiety, for example, a pyrazolyl or imidazolyl ring to decrease CNS MPO scores in order to reduce passive BBB permeability. Four compounds , , , and , when administered orally, were able to increase intestinal motility during morphine-induced constipation in the carmine red dye assays. Among them, compound (p.o.) improved GI tract motility by 75% while orally administered NAP and methylnaltrexone showed no significant effects at the same dose. Thus, this compound seemed a promising agent to be further developed as an oral treatment for OIC.
Topics: Analgesics, Opioid; Constipation; Humans; Ligands; Naltrexone; Narcotic Antagonists; Opioid-Induced Constipation; Receptors, Opioid, mu
PubMed: 35255683
DOI: 10.1021/acs.jmedchem.1c02185 -
Frontiers in Oncology 2021Opioids are administered to cancer patients in the period surrounding tumour excision, and in the management of cancer-associated pain. The effects of opioids on tumour... (Review)
Review
Opioids are administered to cancer patients in the period surrounding tumour excision, and in the management of cancer-associated pain. The effects of opioids on tumour growth and metastasis, and their consequences on disease outcome, continue to be the object of polarised, discrepant literature. It is becoming clear that opioids contribute a range of direct and indirect effects to the biology of solid tumours, to the anticancer immune response, inflammation, angiogenesis and importantly, to the tumour-promoting effects of pain. A common misconception in the literature is that the effect of opioid agonists equates the effect of the mu-opioid receptor, the major target of the analgesic effect of this class of drugs. We review the evidence on opioid receptor expression in cancer, opioid receptor polymorphisms and cancer outcome, the effect of opioid antagonists, especially the peripheral antagonist methylnaltrexone, and lastly, the evidence available of a role for opioids through non-opioid receptor mediated actions.
PubMed: 35004315
DOI: 10.3389/fonc.2021.792290