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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 -
BMC Palliative Care 2014Opioid-induced constipation (OIC) is one of the major symptoms in palliative care with a prevalence of 30-50%. Methylnaltrexone for the treatment of OIC is significantly...
Clinical evaluation of the efficacy of methylnaltrexone in resolving constipation induced by different opioid subtypes combined with laboratory analysis of immunomodulatory and antiangiogenic effects of methylnaltrexone.
BACKGROUND
Opioid-induced constipation (OIC) is one of the major symptoms in palliative care with a prevalence of 30-50%. Methylnaltrexone for the treatment of OIC is significantly more effective than placebo, but only in about fifty percent of the patients regardless of dose increase. Dose increases cause increased toxicity without additional efficacy, and are therefore not recommended. While methylnaltrexone is a μ-receptor antagonist, only a few opioids are solely μ-receptor agonists. Therefore, the response to methylnaltrexone may be determined by the receptor-profile of a specific opioid. In addition, methylnaltrexone may also affect the immune system and angiogenesis as was found in pre-clinical studies. Primary aim of this study is to determine differences in the efficacy of methylnaltrexone prescribed to resolve opioid induced constipation between three commonly used opioid subtypes: morphine sulphate, oxycodone and fentanyl. Secondary aim is to explore potential immunomodulatory and antiangiogenic effects of methylnaltrexone.
METHODS
In this multi-center, prospective, parallel group trial we will evaluate the efficacy of methylnaltrexone in resolving OIC occurring as a side effect of the most common opioid subtypes: morphine, oxycodone and fentanyl. In total 195 patients with OIC despite prophylactic laxatives will receive methylnaltrexone every other day up to fourteen days. Patients will report its effect in a laxation diary. Group allocation is based on the opioid type the patient is using. At the start and end of the study period patients complete the Bowel Function Index questionnaire. A subgroup of the patients will donate blood for analysis of immunomodulatory- and anti-angiogenic effects of methylnaltrexone.
DISCUSSION
In this study we aim to determine the efficacy of methylnaltrexone per opioid subtype to reduce constipation. We expect that the outcome of this study will improve the clinical use of methylnaltraxone.
TRIAL REGISTRATION
This trial is registered at clinicaltrials.gov: NCT01955213 and in the Dutch trial register: NTR4272.
PubMed: 25165428
DOI: 10.1186/1472-684X-13-42 -
The Cochrane Database of Systematic... May 2015This article describes the second update of a Cochrane review on the effectiveness of laxatives for the management of constipation in people receiving palliative care.... (Review)
Review
BACKGROUND
This article describes the second update of a Cochrane review on the effectiveness of laxatives for the management of constipation in people receiving palliative care. Previous versions were published in 2006 and 2010 where we also evaluated trials of methylnaltrexone; these trials have been removed as they are included in another review in press. In these earlier versions, we drew no conclusions on individual effectiveness of different laxatives because of the limited number of evaluations. This is despite constipation being common in palliative care, generating considerable suffering due to the unpleasant physical symptoms and the availability of a wide range of laxatives with known differences in effect in other populations.
OBJECTIVES
To determine the effectiveness and differential efficacy of laxatives used to manage constipation in people receiving palliative care.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library), MEDLINE, EMBASE, CINAHL and Web of Science (SCI & CPCI-S) for trials to September 2014.
SELECTION CRITERIA
Randomised controlled trials (RCTs) evaluating laxatives for constipation in people receiving palliative care.
DATA COLLECTION AND ANALYSIS
Two authors assessed trial quality and extracted data. The appropriateness of combining data from the studies depended upon clinical and outcome measure homogeneity.
MAIN RESULTS
We identified five studies involving the laxatives lactulose, senna, co-danthramer, misrakasneham, docusate and magnesium hydroxide with liquid paraffin. Overall, the study findings were at an unclear risk of bias. As all five studies compared different laxatives or combinations of laxatives, it was not possible to perform a meta-analysis. There was no evidence on whether individual laxatives were more effective than others or caused fewer adverse effects.
AUTHORS' CONCLUSIONS
This second update found that laxatives were of similar effectiveness but the evidence remains limited due to insufficient data from a few small RCTs. None of the studies evaluated polyethylene glycol or any intervention given rectally. There is a need for more trials to evaluate the effectiveness of laxatives in palliative care populations. Extrapolating findings on the effectiveness of laxatives evaluated in other populations should proceed with caution. This is because of the differences inherent in people receiving palliative care that may impact, in a likely negative way, on the effect of a laxative.
Topics: Analgesics, Opioid; Anthraquinones; Cathartics; Constipation; Humans; Lactulose; Magnesium Hydroxide; Naltrexone; Palliative Care; Paraffin; Quaternary Ammonium Compounds; Randomized Controlled Trials as Topic; Senna Extract
PubMed: 25967924
DOI: 10.1002/14651858.CD003448.pub4 -
Ugeskrift For Laeger Aug 2016The evidence for treatment of constipation in palliative care patients is poor. The condition of these patients is often complex, and results from studies performed in... (Review)
Review
The evidence for treatment of constipation in palliative care patients is poor. The condition of these patients is often complex, and results from studies performed in other patient groups cannot be extrapolated unconditionally. However, macrogol (polyethylene glycol), lactulose and sodium picosulphate seem to be well tolerated, and methylnaltrexone could be used in opioid-induced constipation, if the patients are not at risk from gastrointestinal perforation. The patients should be offered quiet and private surroundings, and attention should be payed to securing an optimal body position for defecation.
Topics: Analgesics, Opioid; Constipation; Defecation; Evidence-Based Medicine; Humans; Laxatives; Palliative Care; Posture
PubMed: 27550785
DOI: No ID Found -
Journal of Pain Research 2018To evaluate the safety and efficacy of oral methylnaltrexone for opioid-induced constipation (OIC).
Oral methylnaltrexone is efficacious and well tolerated for the treatment of opioid-induced constipation in patients with chronic noncancer pain receiving concomitant methadone.
PURPOSE
To evaluate the safety and efficacy of oral methylnaltrexone for opioid-induced constipation (OIC).
PATIENTS AND METHODS
This was a post hoc analysis of patients receiving methadone in a randomized, double-blind, placebo-controlled, Phase 3 trial. The trial included adults with chronic noncancer pain for ≥2 months receiving opioid doses ≥50 mg/day of oral morphine equivalents for ≥14 days and with a history of OIC. Patients were assigned to oral methylnaltrexone (150, 300, or 450 mg) or placebo once daily (QD) for 4 weeks followed by 8 weeks as needed. Percentage of dosing days that resulted in a rescue-free bowel movement (RFBM) within 4 hours of dosing was assessed during QD dosing (primary efficacy endpoint). Other endpoints included percentage of responders (ie, ≥3 RFBMs/week, with an increase of ≥1 RFBM/week from baseline for ≥3 of the 4 weeks) during QD dosing and change in weekly number of RFBMs. Adverse events were assessed.
RESULTS
Concomitant methadone was reported in 120 patients (oral methylnaltrexone: 150 mg [n=33], 300 mg [n=30], and 450 mg [n=31]; placebo [n=26]). Oral methylnaltrexone-treated patients had significant increases in mean percentage of dosing days with RFBMs within 4 hours of dosing during weeks 1-4 with 300 mg (33.6%; <0.01) and 450 mg (38.2%; <0.001) vs placebo; improvements with 150 mg (20.0%) vs placebo (15.1%) did not reach statistical significance. The percentage of responders was greater vs placebo, but not significant, for the higher doses during the QD period (150 mg [39.4%], 300 mg [60.0%], 450 mg [67.7%], and placebo [38.5%]). Change from baseline in the mean number of weekly RFBMs (weeks 1-4) was significantly greater with oral methylnaltrexone 450 mg vs placebo (least-squares mean difference vs placebo, 1.2; =0.04); no significant differences were found for 300 or 150 mg. Oral methylnaltrexone was well tolerated at all doses; few patients discontinued treatment.
CONCLUSION
Oral methylnaltrexone, particularly 450 mg, was efficacious and safe for treating OIC in these patients.
PubMed: 30425563
DOI: 10.2147/JPR.S160625 -
Critical Care (London, England) 2008Constipation is the most common gastrointestinal complication associated with opioid therapy in chronic pain patients, and also frequently occurs in sedated intensive...
Constipation is the most common gastrointestinal complication associated with opioid therapy in chronic pain patients, and also frequently occurs in sedated intensive care unit patients. Conventional therapy may not provide sufficient relief from constipation, which can be severe enough to limit opioid use or the dose. In a recent study on terminally ill patients suffering from laxative-resistant opioid-induced constipation, Thomas and colleagues demonstrated subcutaneous methylnaltrexone to rapidly induce defecation. This appealing result might also have favourable prospects for intensive care patients, as their outcome is often codetermined by recovery of bowel functioning.
Topics: Analgesics, Opioid; Constipation; Critical Care; Humans; Narcotic Antagonists
PubMed: 18598388
DOI: 10.1186/cc6930 -
Translational Research : the Journal of... Jul 2017We have previously shown that topical opioids including morphine and its congeners promote healing of full thickness ischemic wounds in rats. We examined the...
We have previously shown that topical opioids including morphine and its congeners promote healing of full thickness ischemic wounds in rats. We examined the contribution of mu opioid receptor (MOPr)-mediated healing of full thickness ischemic wounds using MOPr and delta or kappa opioid receptor knockout (KO) mice. Wound closure in the early (day 5) as well as later phases was delayed in topical morphine or PBS-treated MOPr-KO mice compared with reciprocal treatments of wounds in wild-type (WT) mice. MOPr expression was significantly upregulated at 30 min in the wound margins and colocalized with wound margins and vasculature in the epidermal and dermal layers of the skin. We next examined whether neuropeptide expression was involved in the mechanism of MOPr-mediated wound closure. Substance P (SP) and calcitonin gene-related peptide immunoreactivity (ir) was significantly increased in the skin of MOPr-KO mice as compared with WT mice. Neuropeptide-ir was increased significantly in PBS-treated wounds of MOPr and WT mice, but morphine treatment reduced neuropeptide immunoreactivity in both as compared with PBS. Wounding of keratinocytes led to the release of opioid peptide beta-endorphin (β-END) in conditioned medium, which stimulated the proliferation of endothelial cells. MOPr-selective (D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2, CTOP) and nonselective OPr antagonist naloxone-inhibited endothelial proliferation induced by wounded keratinocyte-conditioned medium. In addition, accelerated wound area closure in vitro by morphine was suppressed by methylnaltrexone, a nonselective OPr antagonist with high affinity for MOPr. Morphine and its congeners stimulated the proliferation of endothelial cells from WT mice but not those from MOPr-KO mice. Furthermore, morphine-induced mitogen-activated protein kinase/extracellular signal-regulated kinase phosphorylation in endothelial cells was significantly decreased in MOPr-KO mice as compared with WT mice. Collectively, these data suggest that MOPr plays a critical role in the proliferation phase with the formation of granulation tissue during wound healing.
Topics: Administration, Topical; Analgesics, Opioid; Animals; Gene Expression Regulation; Humans; Ischemia; Keratinocytes; Mice; Mice, Knockout; Morphine; Receptors, Opioid; Up-Regulation; Wound Healing
PubMed: 28554003
DOI: 10.1016/j.trsl.2017.05.003 -
Paediatrics & Child Health 2021Opioid-induced constipation (OIC) is a common and important problem in paediatric palliative care, critical care, and postoperative settings. Treatment for OIC is often...
BACKGROUND AND OBJECTIVE
Opioid-induced constipation (OIC) is a common and important problem in paediatric palliative care, critical care, and postoperative settings. Treatment for OIC is often ineffective and limited by enteral intake. A new class of drugs called peripherally acting mu-opioid receptor antagonists (PAMORAs) have been shown to be effective treatments of OIC in adults, including the agents methylnaltrexone and naloxegol. Data in children are limited to several small case reports, mostly in the palliative care setting. The goal of this study was to evaluate the effectiveness and safety of methylnaltrexone and naloxegol in hospitalized children, including those with critical illness.
METHODS
We conducted a retrospective study of all children admitted to the Stollery Children's Hospital in Edmonton (Canada) who received either methylnaltrexone or naloxegol for OIC. The primary outcome was median time to first bowel movement (BM) after the first dose of PAMORA.
RESULTS
A total of 27 patients were included in the study. Kaplan-Meier survival analysis showed the median time to the first BM after the first dose of PAMORA was 15.5 hours. Seventeen (63%) patients had laxation within 24 hours of first dose. No significant adverse events were observed.
CONCLUSION
This study is the largest to date to evaluate efficacy and safety of PAMORAs in children. Future studies should be prospective and include larger numbers of patients with critical illness and postoperative OIC as indications for treatment.
PubMed: 33747318
DOI: 10.1093/pch/pxz165 -
Scientific Reports Jul 2019Opioid-induced constipation (OIC) has become increasingly prevalent with the rise of prescription opioid use and can significantly impact quality of life, especially in...
Opioid-induced constipation (OIC) has become increasingly prevalent with the rise of prescription opioid use and can significantly impact quality of life, especially in patients with advanced illness. Methylnaltrexone has proven effective in treating cancer patients with OIC who have not responded adequately to conventional laxative therapy, though use is relatively contraindicated in those with peritoneal carcinomatosis due to theoretical risk and reported cases of perforation. The aim of this study was to evaluate the safety of methylnaltrexone in patients with carcinomatosis. We performed a retrospective review of 3058 pediatric and adult patients who received methylnaltrexone at Memorial Sloan Kettering Cancer Center from 2009-2016. Data collected included age, cancer diagnosis, history of abdominal surgery, prior radiation therapy, evidence of peritoneal carcinomatosis, and complications. Charts were reviewed for any complications at 24 hours, 72 hours, and one week following drug administration, as well as at present. We identified 3058 patients (median age 56, range 1-95) who received a total of 3995 doses of methylnaltrexone. Three hundred thirty three (median age 55, range 4-88) had peritoneal carcinomatosis. The most common primary malignancies included pancreatic (17.7%), ovarian (13.5%), colon (7.2%), and lung (6.6%). 228/333 (68.4%) had a history of abdominal surgery and 85/333 (25.5%) underwent prior radiation therapy. Three patients had adverse outcomes or complications, with only one (0.3%) thought to be related to methylnaltrexone use. To our knowledge, this is the largest study to evaluate the outcomes of patients with carcinomatosis receiving methylnaltrexone and the first to include pediatric patients. We found one perforation attributed to methylnaltrexone. Methylnaltrexone should be considered for treatment of refractory OIC in cancer patients with peritoneal carcinomatosis due to low risk of complications.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Analgesics, Opioid; Child; Child, Preschool; Constipation; Female; Humans; Infant; Male; Middle Aged; Naltrexone; Peritoneal Neoplasms; Quaternary Ammonium Compounds; Retrospective Studies; Treatment Outcome; Young Adult
PubMed: 31270339
DOI: 10.1038/s41598-019-44864-2 -
Clinical Medicine Insights. Oncology 2011Constipation, one of the major side effects of opiates used in palliative care, can impair patients' quality of life to a point where it prevents sufficient pain...
Constipation, one of the major side effects of opiates used in palliative care, can impair patients' quality of life to a point where it prevents sufficient pain control. Methylnaltrexone is a novel μ-receptor antagonist, which does not pass the blood brain barrier. It is licensed to treat opiate induced constipation for patients with advanced diseases. This review article presents an overview of pharmacology and safety of its application, evidence of its efficacy and economic aspects of its use in clinical practice. Available data are limited but strongly suggest that methylnaltrexone causes laxation in less than 24 hours for at least half of those patients over the first two weeks of usage without impairing pain control or causing serious adverse effects. To avoid danger of gastrointestinal perforation it is contraindicated for patients at risk for that complication. More research is needed to evaluate its long-term efficacy and economic impact.
PubMed: 21836816
DOI: 10.4137/CMO.S4867