Relistor (methylnaltrexone bromide) / Ono Pharma, Lantheus, Bausch Health - LARVOL DELTA

Combined Efficacy of Methylnaltrexone and Naloxegol in Managing a Case of Neurogenic and Opioid-Induced Constipation (ACG 2025) - "His bowel regimen is polyethylene glycol 17g 3 times a day, lubiprostone 24mcg daily, 2 tablet of senna 8.6mg twice daily, and naloxegol 12.5mg daily. (2020), which show methylnaltrexone's efficacy in opioid-treated patients. While promising, further research is needed to assess the long-term safety and efficacy of this combined approach in similar patient populations."

Clinical • CNS Disorders • Constipation • Gastroenterology • Gastrointestinal Disorder • Inflammatory Bowel Disease • Multiple Sclerosis

The Double Duct Dilemma: When Methadone Mimics Malignancy (ACG 2025) - "The hospitalization was complicated by persistent opioid-induced constipation, which responded to methylnaltrexone, and the patient was discharged with outpatient surgical referral for elective cholecystectomy. This case highlights a clinically relevant association between chronic methadone use and the double duct sign. While MMT use remains prevalent, specialists should remain vigilant for its potential to mimic more serious conditions. Recognizing this association may help avoid unnecessary invasive procedures and guide individualized diagnostic and therapeutic strategies.Figure: Double Duct on MRCPFigure: Double Duct EUS"

Cholestasis • Constipation • Gastroenterology • Gastrointestinal Disorder • Oncology • Substance Abuse

BUPROPRION OVERDOSE LEADING TO MEDICATION-INDUCED COLONIC PSEUDO-OBSTRUCTION (CHEST 2025) - "Patient was initiated on propofol and fentanyl for sedation, though the fentanyl was rapidly titrated off due to interactive effects with bupropion. The patient briefly required hydromorphone for pain adjunct...Additionally, opioid confounding was also reversed with methylnaltrexone. This case adds to the case log of patients who develop colonic pseudo-obstructions in the setting of bupropion overdose."

Addiction (Opioid and Alcohol) • Anesthesia • Bipolar Disorder • Cardiovascular • CNS Disorders • Depression • Epilepsy • Mood Disorders • Psychiatry

METHYLNALTREXONE-INDUCED OPIOID WITHDRAWAL CASE REPORT (CHEST 2025) - "He was not currently on methadone or suboxone at time of arrival. In the hospital, patient was started on methadone alongside ketamine, oxycodone and nonopioid agents...Patient tolerated the initial dilaudid well with improvement of his symptoms... Our case today highlights a rare occurrence of methylnaltrexone inducing opioid withdrawals which illustrates that further additional studies are needed to better understand other mechanisms of action that could have triggered this event."

Case report • Clinical • Cardiovascular • Constipation • Gastroenterology • Gastrointestinal Disorder • Hepatitis C • Hepatology • Infectious Disease • Inflammation

Roles of Peripheral and Central µ1-Opioid Receptors in the Fentanyl-Induced Cardiorespiratory Responses. (PubMed, Am J Physiol Lung Cell Mol Physiol) - "The same protocols were performed after: naloxone (NLX) and naloxone methiodide (NLM) to systemically and peripherally antagonize ORs respectively (Study II); CTAP and methylnaltrexone (MNTX) to systemically and peripherally block μ-ORs (Study III); and naloxonazine (NLZ) to systemically block μ1-ORs (Study IV). NLZ nearly abolished the fentanyl-evoked responses. Our results indicate that peripherally restricted OR (particularly μ1-OR) antagonism prevents the fentanyl-induced immediate apnea, but fails to change the subsequent respiratory depression."

Journal • Addiction (Opioid and Alcohol) • Anesthesia • Cardiovascular • CNS Disorders • Depression • Psychiatry

Management of constipation in people receiving palliative care. (PubMed, Aust J Gen Pract) - "Management involves treatment of reversible causes, if appropriate, as well as both non-pharmacological and pharmacological interventions. Recommended laxatives for use in palliative care are osmotic laxatives and stimulant laxatives. Prophylactic use of laxatives when prescribing opioids is essential. Methylnaltrexone can be used to manage opioid-induced constipation but should be avoided in patients with bowel obstruction."

Journal • Constipation • Gastroenterology • Gastrointestinal Disorder • Palliative care

Treatment of Opioid-Induced Constipation: Inducing Laxation and Understanding the Risk of Gastrointestinal Perforation. (PubMed, J Clin Gastroenterol) - "Management of OIC includes treatment with over-the-counter laxatives and peripherally acting μ-opioid receptor antagonists (PAMORAs; methylnaltrexone, naloxegol, naldemedine). Appropriate patient selection during laxation therapy for OIC, regardless of treatment plan, involves consideration of the overall risk versus benefit in patients at increased risk of perforation due to comorbid medical conditions, concurrent medications, or recent gastrointestinal procedures. After initiating treatment for OIC, clinicians should assess the effectiveness of laxation therapy and carefully monitor for signs of gastrointestinal perforation."

Journal • Constipation • Gastroenterology • Gastrointestinal Disorder • Pain

RATES OF MEDICAL TREATMENT FOR ALCOHOL USE DISORDER DURING ADMISSION FOR ACUTE PANCREATITIS (DDW 2025) - "Treatments for AUD included consult to addiction medicine or social worker or discharge prescription for disulfiram, naltrexone, methylnaltrexone IM, acamprosate, topiramate, gabapentin, or baclofen. Even lower rates (~20%) received a prescription for AUD at hospital discharge. Additional investigations are needed to understand barriers to implementation of alcohol risk factor reduction and its effect on pancreatitis-related outcomes."

Addiction (Opioid and Alcohol) • Gastroenterology • Hepatology • Pancreatitis

Substrate-specific inhibition of organic cation transporter 1 revealed using a multisubstrate drug cocktail. (PubMed, Drug Metab Dispos) - "Here, we describe a multisubstrate drug cocktail that allows for the simultaneous testing of drug-drug interactions using 8 different victim drugs: fenoterol, salbutamol, sumatriptan, zolmitriptan, ipratropium, trospium, methylnaltrexone, and metformin...Group 1 comprised verapamil, quinidine, fenoterol, and ipratropium, and group 2 comprised metformin, sumatriptan, and trimethoprim...Here, we demonstrate this for organic cation transporter 1 (OCT1, SLC22A1) and presents a drug cocktail designed to identify varying inhibitory potencies in vitro and prevent false-negative drug-drug interaction results during early drug development. This approach can be extended to other polyspecific drug transporters."

Journal • SLC22A1

SEVERE DYSPHAGIA FOLLOWING MAGNETIC SPHINCTER AUGMENTATION: A CASE REPORT (DDW 2025) - "The patient had constipation despite Relistor and stool softeners...GERD symptoms did not improve with lansoprazole twice daily and Pepcid at bedtime... The LINX procedure is one of the GERD treatments. We must balance disease management with awareness of treatment-related complications, which can significantly impact patient outcomes, as shown in this case. To maximize the benefits of this promising intervention, more research is needed to improve patient selection criteria, procedural safety, and adverse event risk."

Case report • Clinical • Barrett Esophagus • Cardiovascular • Constipation • Gastroesophageal Reflux Disease • Gastrointestinal Disorder • Genetic Disorders • Hypertension • Obesity • Pain

SEVERE DYSPHAGIA FOLLOWING MAGNETIC SPHINCTER AUGMENTATION: A CASE REPORT (SSAT 2025) - "The patient had constipation despite Relistor and stool softeners...GERD symptoms did not improve with lansoprazole twice daily and Pepcid at bedtime... The LINX procedure is one of the GERD treatments. We must balance disease management with awareness of treatment-related complications, which can significantly impact patient outcomes, as shown in this case. To maximize the benefits of this promising intervention, more research is needed to improve patient selection criteria, procedural safety, and adverse event risk."

Case report • Clinical • Barrett Esophagus • Cardiovascular • Constipation • Gastroenterology • Gastroesophageal Reflux Disease • Gastrointestinal Disorder • Genetic Disorders • Hypertension • Obesity • Pain

Gastrointestinal Transit Time Assessed Using a CT-Based Radiopaque Marker Method in Patients With Acute Pancreatitis During Methylnaltrexone Treatment. (PubMed, Neurogastroenterol Motil) - "Our CT-based method was feasible in hospitalized patients with AP. Methylnaltrexone did not change gastrointestinal transit compared with placebo. However, laxative therapy was more frequent with the placebo."

Journal • Gastrointestinal Disorder • Immunology • Inflammation • Pancreatitis • Systemic Inflammatory Response Syndrome

Perioperative bowel regimens following posterior spinal fusions for adolescent idiopathic scoliosis: a systematic review. (PubMed, Ann Med Surg (Lond)) - "There is limited evidence to demonstrate any specific perioperative bowel regimen will decrease postpreparative bowel morbidity and/or length of stay. While not a treatment in isolation, oral methylnaltrexone may be a safe and effective adjunct to standard postoperative bowel regimens and may have a better patient tolerance profile."

Journal • Pain

Chronic Widespread Pain in HIV: Novel Mechanisms and Therapeutics (clinicaltrials.gov) - P=N/A | N=200 | Recruiting | Sponsor: Florida International University | Trial primary completion date: Jun 2025 ➔ Nov 2025

Trial primary completion date • Human Immunodeficiency Virus • Infectious Disease • Pain

Methylnatrexone In Resectable Head and Neck Squamous Cell Carcinoma (MINK). A "Window of Opportunity" Pilot Study. (clinicaltrials.gov) - P4 | N=25 | Recruiting | Sponsor: M.D. Anderson Cancer Center | Trial completion date: Jun 2026 ➔ Dec 2025 | Trial primary completion date: Jun 2026 ➔ Dec 2025

Trial completion date • Trial primary completion date • Head and Neck Cancer • Oncology • Solid Tumor • Squamous Cell Carcinoma • Squamous Cell Carcinoma of Head and Neck

Evaluation of the Use of Methylnaltrexone According to Product Labeling (ASHP 2024) - No abstract available

Evaluating Appropriate Use of Methylnaltrexone for Opioid Induced Constipation (ASHP 2024) - No abstract available

Constipation • Gastroenterology • Gastrointestinal Disorder

Medication Utilization Evaluation of Subcutaneous Methylnaltrexone for Opioid Induced Constipation in a Quaternary Care Teaching Hospital (ASHP 2024) - No abstract available

Clinical • Constipation • Gastroenterology • Gastrointestinal Disorder

Subcutaneous Methylnaltrexone Treatment of Opioid-Induced Constipation in Adults with Rheumatic Conditions (ACR Convergence 2024) - "The aim of this subgroup analysis was to assess the efficacy/safety of methylnaltrexone for OIC in patients who participated in a phase 3 trial and had ankylosing spondylitis (AS), fibromyalgia, rheumatoid arthritis (RA), or osteoarthritis (OA). A phase 3, randomized, double-blind, placebo-controlled trial enrolled adults with chronic (≥2 months) noncancer pain taking ≥50 mg oral morphine equivalent dose (MED) for ≥2 weeks who had a mean of < 3 bowel movements/week. Subcutaneous methylnaltrexone QOD was efficacious, with a rapid onset of action, and generally well tolerated for the treatment of OIC in adults with rheumatic disease. Figure 1. Percentage of Patients With a Bowel Movement Within 4 Hours of the First Treatment Dose"

Clinical • Ankylosing Spondylitis • Constipation • Fibromyalgia • Gastroenterology • Gastrointestinal Disorder • Immunology • Infectious Disease • Musculoskeletal Pain • Nephrology • Oncology • Osteoarthritis • Pain • Rheumatoid Arthritis • Rheumatology • Seronegative Spondyloarthropathies

Opioid treatment restricts response to immunotherapy in oral squamous cell carcinoma (SITC 2024) - "A syngeneic orthotopic mouse model of oral squamous cell carcinoma was used to study the impact of morphine (10mg/kg, 2x daily for 4.5 days) and OPRM1 antagonism (methylnaltrexone (10mg/kg), axelopran (1mg/kg)) on tumor infiltrating immune cells, tumor growth and anti-tumor efficacy of anti-PD1 monoclonal antibody treatment...Ethics Approval All procedures were approved by the University of Pittsburgh Institutional Animal Care and Use Committee (Protocol #: 23093881) and performed in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals. The ARRIVE Essential 10 were followed for all preclinical experimental designs."

IO biomarker • Oncology • Oral Cancer • Squamous Cell Carcinoma • Squamous Cell Carcinoma of Head and Neck • CD8 • FOXP3 • OPRM1 • PTPRC

Methylnaltrexone for Intractable Opioid-Induced Paralytic Ileus in a Postpartum Patient with Sickle Cell Disease (ASA 2024) - "Following this switch and the second dose of methylnaltrexone, she had return of bowel function, reducing her opioid requirement.We hypothesize that the initial ineffectiveness of methylnaltrexone may be due to the higher binding affinity of hydromorphone compared to both fentanyl and methylnaltrexone at µ-opioid receptors. Switching to fentanyl may have allowed methylnaltrexone to compete more effectively."

Clinical • Genetic Disorders • Hematological Disorders • Pain • Sickle Cell Disease

Methylnaltrexone's Effect on Cholestasis in Trauma Patients. (PubMed, Cureus) - "The median age between the treatment and control groups did not show statistically significant differences. Sex was also not statistically different between the two groups with 38 males and 18 females in the treatment group as compared to 39 males and 17 females in the control group with a p-value of 0.86. The median hospital length of stay was longer in the treatment group at 13 days compared to only one day in the control group which was statistically different with a p-value of <.001. ICU length of stay was also found to be statistically different between the treatment and control groups with 4 and 0 days respectively and a p-value of <.001. Mortality between the two groups was also higher in the treatment group with five patients in the treatment group not surviving to discharge as compared to one patient in the control group (p-value = .044). Both groups had one patient who met the criteria for cholestasis representing an overall..."

Journal • Cardiovascular • Cholestasis • Congestive Heart Failure • Fibrosis • Gastroenterology • Heart Failure • Hepatology • Immunology • Infectious Disease • Septic Shock

THE EFFECT OF A PERIPHERALLY ACTING OPIOID ANTAGONIST ON ACUTE PANCREATITIS: A MULTICENTRE RANDOMISED CONTROLLED TRIAL (UEGW 2024) - "At 48 hours, we found no differences between groups in pain severity (difference, 0.0 [95% CI, -0.8 to 0.9]; P=0.94), pain interference (difference, -0.3 [95% CI, -1.4 to 0.8]; P=0.55), and morphine equivalent doses (difference, 6.5 mg [95% CI, -2.1 to 15.2]; P=0.14). Methylnaltrexone treatment did not change the outcome of acute pancreatitis. Indirectly, the study supports that short-term opioid use is safe for pain control in acute pancreatitis."

Clinical • Gastrointestinal Disorder • Nephrology • Pain • Pancreatitis • Renal Disease

Emerging therapies for opioid-induced constipation: what can we expect? (PubMed, Expert Opin Pharmacother) - "Key topics included the efficacy of peripherally acting mu-opioid receptor antagonists (PAMORAs) such as methylnaltrexone, naloxegol, and naldemedine, which specifically target opioid-induced gut dysfunction. Other treatment options, including intestinal secretagogues like lubiprostone and linaclotide, selective 5-HT receptor agonists such as prucalopride, and emerging adjunctive therapies like transcutaneous electrical nerve stimulation (TENS) and electroacupuncture were mentioned...Emerging therapies and adjunctive treatments offer promising results but require further validation through rigorous studies. Future research should focus on long-term outcomes, cost-effectiveness, and comparative effectiveness to better address the complex needs of patients with OIC and refine treatment protocols."

Journal • Constipation • Gastroenterology • Gastrointestinal Disorder • Pain

Methylnatrexone In Resectable Head and Neck Squamous Cell Carcinoma (MINK). A "Window of Opportunity" Pilot Study. (clinicaltrials.gov) - P4 | N=25 | Recruiting | Sponsor: M.D. Anderson Cancer Center | Trial completion date: Jun 2024 ➔ Jun 2026 | Trial primary completion date: Jun 2024 ➔ Jun 2026

Trial completion date • Trial primary completion date • Head and Neck Cancer • Oncology • Solid Tumor • Squamous Cell Carcinoma • Squamous Cell Carcinoma of Head and Neck