Chronic opioid induced constipation in patients with nonmalignant pain: challenges and opportunities

Laxative and purgative actions of phytoactive compounds from beetroot juice against loperamide-induced constipation, oxidative stress, and inflammation in rats

BACKGROUND

Chronic constipation is a gastrointestinal functional disorder which affects patient quality of life. Therefore, many studies were oriented to search herbal laxative agents. In this study, we investigated the phytochemical composition of beetroot juice (BJ) and its laxative potential in an experimental model of constipation and colonic dysmotility induced by loperamide (LOP) in Wistar rats.

METHODS

Animals were concurrently pretreated with LOP (3 mg/kg, b.w., i.p.) and BJ (5 and 10 mL/kg, b.w., p.o.), or yohimbine (2 mg/kg, b.w., i.p.), during 1 week. The laxative activity was determined based on the weight, frequency, and water content of the feces matter. The gastric-emptying test and intestinal transit were determined. Colon histology was examined, and oxidative status was evaluated using biochemical-colorimetric methods.

KEY RESULTS

The in vivo study revealed that LOP induced a significant inhibition of gastrointestinal motility, negative consequences on defecation parameters, oxidative stress, and colonic mucosa lesions. Conversely, administration of BJ reestablished these parameters and restored colonic oxidative balance. Importantly, BJ treatment protected against LOP-induced inflammatory markers (pro-inflammatory cytokines and WBC) and the increase in intracellular mediators such as hydrogen peroxide, free iron, and calcium levels.

CONCLUSIONS & INFERENCES

This study demonstrated that the bioactive compounds in BJ provided an anti-constipation effect by modulating intestinal motility and regulating oxidative stress and inflammation induced by LOP intoxication.

Opioids and the Gastrointestinal Tract: The Role of Peripherally Active µ-Opioid Receptor Antagonists in Modulating Intestinal Permeability

Opioid receptors are found throughout the gastrointestinal tract, including the large intestine. Many patients treated with opioids experience opioid-induced constipation (OIC). Laxatives are not effective in most patients, and in those who do initially respond, the efficacy of laxatives generally diminishes over time. In addition, OIC 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 are a crucial component of innate immunity and are tightly regulated within the gut epithelium. Pathologic µ-opioid receptor (MOR) and toll-like receptor 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 MOR antagonists, including methylnaltrexone, are effective at treating OIC. Benefits extend beyond simply blocking the MOR; 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 MOR 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.

3,3-Dibromoflavanone, a synthetic flavonoid derivative for pain management with antidepressant-like effects and fewer side effects than those of morphine in mice

In the pursuit of new lead compounds with fewer side effects than opioids, the novel synthetic phytochemical core, 3,3-dibromoflavanone (3,3-DBF), has emerged as a promising candidate for pain management. Acute assays demonstrated dose-dependent central and peripheral antinociceptive activity of 3,3-DBF through the μ-opioid receptor. This study aimed to explore repeated administration effects of 3,3-DBF in mice and compare them with morphine. Mice were treated with 3,3-DBF (30 mg/kg), morphine (6 mg/kg), or vehicle for 10 days, alongside single-treatment groups. Unlike morphine, 3,3-DBF demonstrated antinociceptive effects in the hot plate test without inducing tolerance. Locomotor activity and motor coordination tests (evaluated through the inverted screen and rotarod tests) revealed no significant differences between the 3,3-DBF-treated and control groups. The gastrointestinal transit assay indicated that 3,3-DBF did not induce constipation, in contrast to morphine. Furthermore, withdrawal signs assessed with the Gellert-Holtzman scale were not comparable to morphine. Additionally, 3,3-DBF exhibited antidepressant-like activity, reducing immobility time in the forced swimming and tail suspension tests, akin to imipramine. In summary, 3,3-DBF demonstrated antinociceptive effects without inducing tolerance or dependence and exhibited antidepressant properties. These findings highlight the potential of 3,3-DBF as a promising therapeutic agent for pain management and its comorbidities, offering advantages over morphine by minimizing side effects.

Naloxegol versus Methylnaltrexone for Opioid-Induced Constipation in Critically Ill Patients

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; P = 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.

Analysis of differentially expressed lncRNAs and mRNAs associated with slow‑transit constipation

Slow transit constipation (STC) is a refractory gastrointestinal disease, accounting for approximately 13 ∼ 37 % of chronic constipation. However, the molecular mechanism of STC remains poorly understood. Herein, this study aims to identify the key mRNAs and lncRNAs associated with STC. To this end, we performed high-throughput RNA sequencing to identify differentially expressed (DE) mRNAs and lncRNAs in the whole-layer sigmoid intestinal tissues from 4 STC patients and 4 non-STC patients. The identified DE lncRNAs and mRNAs were validated through quantitative real-time PCR. Weighted gene co-expression network analysis (WGCNA) and Pearson correlation analysis were conducted to determine the significantly correlated DE mRNA-lncRNA pairs. A total of 1420 DE lncRNAs and 1634 DE mRNAs were identified. Kyoto Encyclopedia of Genes and Genomes analysis of DE mRNAs indicated that these DE mRNAs might be associated with systemic lupus erythematosus, alcoholism, intestinal immune network for IgA production, inflammatory bowel disease, NF-kappa B signaling pathway. WGCNA and Pearson correlation analyses jointly identified 16,577 significantly correlated DE mRNA-lncRNA pairs. Furthermore, lncRNAs LINC00641, LINC02268, LINC03013 were identified as hub lncRNAs. The protein-protein interaction (PPI) network of proteins encoded by DE mRNAs was established, and PPI-based analysis revealed that Interleukin 2(IL2), CD80 molecule (CD80), interleukin-17A (IL-17A) might play significant roles in the development of STC. This study analyzes the expression profiles of lncRNAs and mRNAs associated with STC. Our findings will contribute to further understanding of the molecular mechanism of STC and provide potential diagnostic or therapeutic biomarkers for STC.

Opioid-induced Constipation: Old and New Concepts in Diagnosis and Treatment

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.

Placental cytochrome P450 methylomes in infants exposed to prenatal opioids: exploring the effects of neonatal opioid withdrawal syndrome on health horizons

Background: Neonatal opioid withdrawal syndrome (NOWS), arises due to increased opioid use during pregnancy. Cytochrome P450 (CYP) enzymes play a pivotal role in metabolizing a wide range of substances in the human body, including opioids, other drugs, toxins, and endogenous compounds. The association between CYP gene methylation and opioid effects is unexplored and it could offer promising insights. Objective: To investigate the impact of prenatal opioid exposure on disrupted CYPs in infants and their anticipated long-term clinical implications. Study Design: DNA methylation levels of CYP genes were analyzed in a cohort of 96 placental tissues using Illumina Infinium MethylationEPIC (850 k) BeadChips. This involved three groups of placental tissues: 32 from mothers with infants exposed to opioids prenatally requiring pharmacologic treatment for NOWS, 32 from mothers with prenatally opioid-exposed infants not needing NOWS treatment, and 32 from unexposed control mothers. Results: The study identified 20 significantly differentially methylated CpG sites associated with 17 distinct CYP genes, with 14 CpGs showing reduced methylation across 14 genes (CYP19A1, CYP1A2, CYP4V2, CYP1B1, CYP24A1, CYP26B1, CYP26C1, CYP2C18, CYP2C9, CYP2U1, CYP39A1, CYP2R1, CYP4Z1, CYP2D7P1 and), while 8 exhibited hypermethylation (CYP51A1, CYP26B1, CYP2R1, CYP2U1, CYP4X1, CYP1A2, CYP2W1, and CYP4V2). Genes such as CYP1A2, CYP26B1, CYP2R1, CYP2U1, and CYP4V2 exhibited both increased and decreased methylation. These genes are crucial for metabolizing eicosanoids, fatty acids, drugs, and diverse substances. Conclusion: The study identified profound methylation changes in multiple CYP genes in the placental tissues relevant to NOWS. This suggests that disruption of DNA methylation patterns in CYP transcripts might play a role in NOWS and may serve as valuable biomarkers, suggesting a future pathway for personalized treatment. Further research is needed to confirm these findings and explore their potential for diagnosis and treatment.

Therapeutic effects of Bombax ceiba flower aqueous extracts against loperamide-induced constipation in mice

CONTEXT

Bombax ceiba Linnaeus (Bombacaceae) is known as silk cotton tree, the flowers of which are used in many medicinal applications.

OBJECTIVE

To investigate the therapeutic effect of B. ceiba flower aqueous extracts (BCE) against loperamide-induced constipation and characterize the chemical composition of BCE.

MATERIALS AND METHODS

Sixty male Kunming mice were divided into control (saline), model (10 mg/kg loperamide + saline), phenolphthalein (10 mg/kg loperamide + 10 mg/kg phenolphthalein) and different dosage of BCE (10 mg/kg loperamide + 40, 80 and 160 mg/kg BCE, respectively) groups, and received intragastric administrations for eight days. Faecal water content, number of faeces, first black-stool defecation time and gastrointestinal transit rates were evaluated. Various biochemical and molecular biomarkers were assessed in blood and colon. UPLC-ESI-QTOF-MS/MS was used to tentatively identify the composition of the BCE.

RESULTS

BCE treatment (160 mg/kg) could increase faecal water (15.75%), faeces number (11.65%), gastrointestinal transit rate (25.37%) and decrease first black-stool defecation time (24.04%). The BCE (80 mg/kg) increased the serum level of motilin (30.62%), gastrin (54.46%) and substance P (18.99%), and decreased somatostatin (19.47%). Additionally, the BCE (160 mg/kg) reduced the mucosal damage, restored colonic goblet cell function, down-regulated the protein expression of AQP₃ (33.60%) and increased c-kit protein expression (11.63%). Twelve known compounds, including protocatechuic acid, chlorogenic acid and rutin, previously reported in B. ceiba, were identified in the BCE.

DISCUSSION AND CONCLUSIONS

This study suggested that BCE is a promising agent for the treatment of constipation.

Safety and Efficacy of Oral Nalbuphine on Postoperative Pain in Hemorrhoidectomy Patients: A Randomized, Double-blind, Placebo-controlled, Pivotal Trial

OBJECTIVES

Severe postoperative pain requiring opioid treatment has been reported in 20% to 40% of hemorrhoidectomy patients. Compared with morphine, nalbuphine offers better hemodynamic stability, a lower risk of respiratory depression, and a lower potential for addiction. Nalbuphine was developed from the intravenous form into an oral form (PHN131) to alleviate moderate-to-severe pain.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled, multiple-dose, parallel-design trial was conducted to evaluate the safety and efficacy of PHN131 in patients undergoing hemorrhoidectomy. Eligible patients were randomly assigned to receive either PHN131 soft capsules containing nalbuphine hydrochloride 60 mg or placebo capsules. Intramuscular diclofenac was the rescue analgesic. Pain was measured by the area under the curve of mean Visual Analog Scale pain intensity scores.

RESULTS

Visual Analog Scale results in patients receiving PHN131 were significantly lower than placebo group scores through 48 hours postoperatively (149.2±75.52 vs. 179.6±65.97; P =0.0301). According to Brief Pain Inventory Short-Form scores, the impact of pain on quality of life was significantly smaller for the PHN131 group than for the placebo group. Time to the first use of diclofenac postoperatively was significantly longer in the PHN131 group than in the placebo group. The cumulative dosage of diclofenac in the PHN131 group was only around half of that in the placebo group ( P <0.0001). Drug-related adverse events were mild-to-moderate and resolved by the treatment end. No drug-related severe adverse events were observed.

DISCUSSION

Our findings demonstrate that PHN131 is effective and well-tolerated in the treatment of moderate-to-severe post hemorrhoidectomy pain and may provide another option for patients to control their pain.

Translational research updates in female health anesthesiology: a narrative review

Background and Objective

Females represent 49.6% of the global population and constitute a significant proportion of surgical patients and hospital admissions. Little is known about the bi-directional effects of sex and anesthetics or the impact of anesthetic interventions on long-term female health outcomes. Sex differences in pain pathways can influence pain experience and treatment effectiveness. The impact of anesthetic management on the recurrence of breast cancer is poorly understood, as are the long-term consequences of cardiovascular disease and safe and effective treatments in pregnancy. This review aims to outline recent advances in translational science in female health anesthesiology research and highlight critical research opportunities in pain, cancer outcomes, and cardiovascular disorders.

Methods

We searched PubMed and summarized relevant articles published in English between December 2021 and June 2022.

Key Content and Findings

Studies reveal sex differences in pain pathways and highlight the importance of sex as a biological variable in experimental designs and translational medicine. Sex differences have also been observed in side effects attributed to opioid analgesics. We summarize some of the neural circuits that might underlie these differences. In the perioperative setting, specific anesthetics are implicated in metastatic seeding potential and acute and chronic pain outcomes, suggesting the importance of anesthetic selection in comprehensive care during oncologic surgery. In the peridelivery setting, preeclampsia, a cardiovascular disorder of pregnancy, affects maternal outcomes; however, biomarkers can risk-stratify females at risk for preeclampsia and hold promise for identifying the risk of adverse neurological and other health outcomes.

Conclusions

Research that builds diagnostic and predictive tools in pain and cardiovascular disease will help anesthesiologists minimize sex-related risks and side effects associated with anesthetics and peri-hospital treatments. Sex-specific anesthesia care will improve outcomes, as will the provision of practical information to patients and clinicians about the effectiveness of therapies and behavioral interventions. However, more research studies and specific analytic plans are needed to continue addressing sex-based outcomes in anesthesiology.

Methylnaltrexone Treatment for Opioid-Induced Constipation in Patients with and without Cancer: Effect of Initial Dose

Purpose

Opioid-induced constipation (OIC) is a common side effect of opioid therapy. Methylnaltrexone (MNTX) is a selective, peripherally acting μ-opioid receptor antagonist, with demonstrated efficacy in treating OIC. We pooled results from MNTX clinical trials to compare responses to an initial dose in patients with chronic cancer and noncancer pain.

Patients and Methods

This post hoc analysis used pooled data from 3 randomized, placebo-controlled studies of MNTX in patients with advanced illness with OIC. Assessments included the proportions of patients achieving rescue-free laxation (RFL) within 4 and 24 hours of the first study drug dose, time to RFL, current and worst pain intensity, and adverse events, stratified by the presence/absence of cancer.

Results

A total of 355 patients with cancer (MNTX n = 198, placebo n = 157) and 163 without active cancer (MNTX n = 83; placebo n = 80) were included. More patients treated with MNTX compared with those who received placebo achieved an RFL within 4 (cancer: MNTX, 61.1% vs placebo,15.3%, p<0.0001; noncancer: MNTX, 62.2% vs placebo, 17.5%, p<0.0001) and 24 hours (cancer: MNTX, 71.2% vs placebo, 41.4%, p<0.0001; noncancer: MNTX, 74.4% vs placebo, 37.5%, p<0.0001) of the initial dose. Cumulative RFL response rates within 4 hours of the first, second, or third dose of study drug were also higher in MNTX-treated patients. The estimated time to RFL was shorter among those who received MNTX and similar in cancer and noncancer patients. Mean pain scores declined similarly in all groups. The most common adverse events in both cancer and noncancer patients were abdominal pain, flatulence, and nausea.

Conclusion

After the first dose, MNTX rapidly induced a laxation response in the majority of both cancer and noncancer patients with advanced illness. Opioid-induced analgesia was not compromised, and adverse events were primarily gastrointestinal in nature. Methylnaltrexone is a well-tolerated and effective treatment for OIC in both cancer and noncancer patients.

Association of preoperative opioid use and postoperative complications following breast reconstruction

BACKGROUND

Previous studies in orthopedics and general surgery have linked negative patient outcomes with preoperative opioid use. In this study, we investigated the association of preoperative opioid use on breast reconstruction outcomes and quality of life (QoL).

METHODS

We reviewed our prospective registry of patients who underwent breast reconstruction for documented preoperative opioid use. Postoperative complications were recorded at 60 days after the first reconstructive surgery and 60 days after the final staged reconstruction. We used a logistic regression model to assess the association between opioid use and postoperative complications, controlling for smoking, age, laterality, BMI, comorbidities, radiation, and previous breast surgery; linear regression to analyze RAND36 scores to evaluate the impact of preoperative opioid use on postoperative QoL, controlling for the same factors; and Pearson chi-squared test to assess factors that may be associated with opioid use.

RESULTS

Of the 354 patients eligible for inclusion, 29 (8.2%) were prescribed preoperative opioids. There were no differences in opioid use by race, BMI, comorbidities, previous breast surgery, or laterality. Preoperative opioids were associated with increased odds of postoperative complications within 60 days after the first reconstructive surgery (OR: 6.28; 95% CI: 1.69-23.4; p = 0.006) and within 60 days after the final staged reconstruction (OR: 8.38; 95% CI: 1.17-59.4; p = 0.03). Among patients using opioids preoperatively, the RAND36 physical and mental scores decreased but were not statistically significant.

CONCLUSION

We found that preoperative opioid use is associated with increased odds of postoperative complications among patients who underwent breast reconstruction and may contribute to clinically significant declines in postoperative QoL.

Effects of Electroacupuncture for Opioid-Induced Constipation in Patients With Cancer in China: A Randomized Clinical Trial

IMPORTANCE

Opioid-induced constipation (OIC) is prevalent among patients treated with opioids for cancer pain. Safe and effective therapies for OIC in patients with cancer remain an unmet need.

OBJECTIVE

To determine the efficacy of electroacupuncture (EA) for OIC in patients with cancer.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial was conducted at 6 tertiary hospitals in China among 100 adult patients with cancer who were screened for OIC and enrolled between May 1, 2019, and December 11, 2021.

INTERVENTIONS

Patients were randomized to receive 24 sessions of EA or sham electroacupuncture (SA) over 8 weeks and then were followed up for 8 weeks after treatment.

MAIN OUTCOMES AND MEASURES

The primary outcome was the proportion of overall responders, defined as patients who had at least 3 spontaneous bowel movements (SBMs) per week and an increase of at least 1 SBM from baseline in the same week for at least 6 of the 8 weeks of the treatment period. All statistical analyses were based on the intention-to-treat principle.

RESULTS

A total of 100 patients (mean [SD] age, 64.4 [10.5] years; 56 men [56.0%]) underwent randomization; 50 were randomly assigned to each group. Among them, 44 of 50 patients (88.0%) in the EA group and 42 of 50 patients (84.0%) in the SA group received at least 20 (≥83.3%) sessions of treatment. The proportion of overall responders at week 8 was 40.1% (95% CI, 26.1%-54.1%) in the EA group and 9.0% (95% CI, 0.5%-17.4%) in the SA group (difference between groups, 31.1 percentage points [95% CI, 14.8-47.6 percentage points]; P < .001). Compared with SA, EA provided greater relief for most OIC symptoms and improved quality of life among patients with OIC. Electroacupuncture had no effects on cancer pain and its opioid treatment dosage. Electroacupuncture-related adverse events were rare, and, if any, all were mild and transient.

CONCLUSIONS AND RELEVANCE

This randomized clinical trial found that 8-week EA treatment could increase weekly SBMs with a good safety profile and improve quality of life for the treatment of OIC. Electroacupuncture thus provided an alternative option for OIC in adult patients with cancer.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03797586.

Management of Opioid-induced Constipation in Older Adults

Opioid-induced constipation (OIC) is a common condition in older adults who may not be responsive to traditional laxative therapy. OIC is defined as new or worsening constipation symptoms that occur with initiation of or altering the dose of opioid analgesia. For adult patients with OIC and noncancer pain, we recommend considering nonpharmacologic interventions (eg, dietary measures, increased physical activity, and biofeedback training) and over-the-counter laxatives, followed by prescription opioid receptor antagonists (methylnaltrexone, naloxegol, and naldemedine) if traditional over-the-counter laxatives fail. Other options may include lubiprostone, linaclotide, plecanatide, and prucalopride; however, these are not indicated for OIC specifically or studied in older adults. Because of the complex nature of absorption, distribution, metabolism, and excretion in the aging population, all agents used to treat OIC must be evaluated individually and reevaluated as patients continue to age. This review will serve as a guide to managing OIC in older adults.

Cumulative Laxation Response with Methylnaltrexone: Implications for Hospitalized Patients with Advanced Illness and Opioid-Induced Constipation

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 (P < 0.0001), and between-treatment comparisons remained significant (P < 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. (Curr Ther Res Clin Exp. 2023; 84:XXX-XXX)© 2023 Elsevier HS Journals, Inc.

Bisacodyl overcomes morphine-induced constipation by decreasing colonic Aquaporin-3 and Aquaporin-4 expression

Introduction: Morphine is an opioid prescribed to treat aches and pains. However, morphine often causes opioid-induced constipation (OIC). Aquaporin (AQP) transporters, especially AQP3 and AQP4, play an essential role in mediating constipation. Bisacodyl is a common laxative used to treat constipation. To date, the effects of bisacodyl on AQP3 and AQP4 expression and the role this interaction plays in constipation are unclear. This study aimed to determine the effects of bisacodyl on AQP3 and AQP4 expression in mice after induction of constipation with morphine.

Materials and methods: The laxative effects of bisacodyl on both acute and chronic morphine-induced constipation were determined. Fecal water content, colonic bead expulsion, and colonic mRNA levels for AQP3 and AQP4 mRNA were measured.

Results and discussion: The administration of morphine to mice resulted in decreased fecal water content, longer bead expulsion times, and increased AQP3 and AQP4 mRNA levels in the colon. Meanwhile, bisacodyl administration prevented the morphine-induced changes in fecal water content, bead expulsion time, and AQP3 and AQP4 mRNA levels in the colons of mice.

Conclusion: This study suggests that bisacodyl may prevent morphine-induced constipation by preventing morphine-induced increases in AQP3 and AQP4 expression in the colon.

Graphical abstract:

The role of gut microbial β-glucuronidase in drug disposition and development

Gut microbial β-glucuronidase (gmGUS) is involved in the disposition of many endogenous and exogenous compounds. Preclinical studies have shown that inhibiting gmGUS activity affects drug disposition, resulting in reduced toxicity in the gastrointestinal tract (GIT) and enhanced systemic efficacy. Additionally, manipulating gmGUS activity is expected to be effective in preventing/treating local or systemic diseases. Although results from animal studies are promising, challenges remain in developing drugs by targeting gmGUS. Here, we review the role of gmGUS in host health under physiological and pathological conditions, the impact of gmGUS on the disposition of phenolic compounds, models used to study gmGUS activity, and the perspectives and challenges in developing drugs by targeting gmGUS.

Pain and Opioid-Induced Gut Microbial Dysbiosis

Opioid-induced dysbiosis (OID) is a specific condition describing the consequences of opioid use on the bacterial composition of the gut. Opioids have been shown to affect the epithelial barrier in the gut and modulate inflammatory pathways, possibly mediating opioid tolerance or opioid-induced hyperalgesia; in combination, these allow the invasion and proliferation of non-native bacterial colonies. There is also evidence that the gut-brain axis is linked to the emotional and cognitive aspects of the brain with intestinal function, which can be a factor that affects mental health. For example, Mycobacterium, Escherichia coli and Clostridium difficile are linked to Irritable Bowel Disease; Lactobacillaceae and Enterococcacae have associations with Parkinson’s disease, and Alistipes has increased prevalence in depression. However, changes to the gut microbiome can be therapeutically influenced with treatments such as faecal microbiota transplantation, targeted antibiotic therapy and probiotics. There is also evidence of emerging therapies to combat OID. This review has collated evidence that shows that there are correlations between OID and depression, Parkinson’s Disease, infection, and more. Specifically, in pain management, targeting OID deserves specific investigations.

Evaluation of a Pharmacist-Driven Protocol for the Treatment of Opioid-Induced Constipation

BACKGROUND

Opioid-induced constipation (OIC) treatment guidelines recommend over-the-counter laxatives as first-line therapy, followed by treatment with a peripherally-acting mu-opioid receptor antagonist (PAMORA) in refractory patients.

OBJECTIVE

To evaluate the ability of a pharmacist-driven OIC protocol to promote increased scheduled laxative use prior to escalation to PAMORA therapy.

METHODS

This retrospective, single-center cohort study evaluated patients 2 years pre- and post-protocol implementation. The primary outcome was the difference in the percentage of patients receiving 2 scheduled laxatives for ≥ 2 days prior to PAMORA therapy pre- and post-protocol. Secondary outcomes included difference in time to first bowel movement after PAMORA initiation, difference in total number of laxative/PAMORA doses administered, and difference in overall estimated total cost. Data was analyzed using chi-squared tests and Student's t tests.

RESULTS

Three-hundred patients were included (150 patients in the pre and post-protocol groups). In the pre-protocol group, 53 patients (35%) received 2 scheduled laxatives for 2 days prior to naloxegol/methylnaltrexone compared to 96 patients (64%) in the postprotocol group (p < 0.0001). One-thousand twenty-one scheduled laxative doses were given pre-protocol versus 1625 doses post-protocol. Average time to first bowel movement was similar between groups (17.7 hours vs 16.0 hours p = 0.441). Estimated total cost of OIC reversal therapy decreased from $20,896.95 to $13,405.47.

CONCLUSION

A pharmacist-driven OIC protocol is associated with an increase in the use of scheduled laxatives prior to PAMORA administration and decreased overall estimated total cost. A larger, prospective study is necessary to assess if this promotes more efficacious OIC.

Extraction of Pectin from Orange Peel and Study of Its Protective Effect Against Loperamide-Induced Impaired Gastrointestinal Motor Functions and Oxidative Stress in Rats

Pectin is a polysaccharide attached to carbohydrates. These are substances exclusively of plant origin. The aim of the present study is to evaluate the laxative effects of orange peel pectin extract (OPPE) against constipation induced by loperamide (LOP) in rats. Rats were equally divided into six groups and treated daily 1 week as follows: Control, LOP (3 mg/kg, body weight [b.w.], Per Os [p.o.]), LOP+yohimbine (2 mg/kg, b.w., i.p.), and LOP+OPPE (6.25, 12.5, and 25 mg/kg, b.w., p.o.). At the end of the experiment, the effects of OPPE were assessed by fecal parameters (numbers, weight, and water content), gastrointestinal transit, gastric emptying, serum metabolic parameter changes, intestinal and colon mucosa oxidative stress, and the histological examination. The defecation test showed that administration of LOP (3 mg/kg, b.w., p.o.) leads to the production of remarkable constipation. Indeed, the number and water content of stools decreased (25.50 [n/24 h] and 29.86%) significantly (P < .05). Acute pretreatment with OPPE significantly and dose dependently accelerated the stool moistening and allowed an increase of stool weight (2.85, 3.61, 3.93 [g/24 h/rat]) as well as the frequency of defecation (47.36, 54.54, and 56.26 [n/24 h]). OPPE also significantly (P < .05) and dose dependently increased the intestinal motility (70.78%, 73.33%, and 75.01%) and gastric emptying. LOP-induced reduction (P < .05) of intestinal secretion was accompanied by a colonic and small bowel oxidative stress status and histological changes, which was attenuated by OPPE treatment. The findings of this study indicate that OPPE possesses an important role in the gastrointestinal motility regulation, and thus lend pharmacological credence to the suggested use of the natural pectin for the treatment, management, and/or control of constipation.

Reducing Opioid-Induced Constipation Post-Cardiac Surgery: An Improvement Project in a Pediatric Cardiac Intensive Care Unit

BACKGROUND

Pain management with opioids and underutilization of prophylaxis for constipation can prolong a patient's hospital length of stay and impede pain management efforts.

PROBLEM

In pediatric postoperative cardiac patients, opioid therapy is a common approach to pain management but often places them at greater risk for constipation due to anatomy and age.

METHODS

A retrospective review of 50 patients' medical records for baseline data was conducted, and a survey evaluated providers' current knowledge and practice.

INTERVENTIONS

The intervention was an electronic order set that provided decision support. Additionally, prophylactic measures were supported by a validated assessment tool that created a common language to report constipation risk.

RESULTS

Although not statistically significant, postintervention data demonstrated a 21.5% decrease in postoperative constipation and a 57% increase in ordered bowel regimens.

CONCLUSION

More focus is needed toward prophylactic bowel regimens to reduce the risk in this already high-risk population.

First-Dose Efficacy of Methylnaltrexone in Patients with Severe Medical Illness and Opioid-Induced Constipation: A Pooled Analysis

BACKGROUND

Opioid-induced constipation (OIC) is a frequent consequence of opioid analgesia that may increase patient risk for emergency department visits and hospitalization. Methylnaltrexone is a peripherally acting µ-opioid receptor antagonist indicated for the treatment of OIC.

OBJECTIVE

To assess the safety and efficacy of a single methylnaltrexone dose.

METHODS

Results were pooled from three randomized, placebo-controlled methylnaltrexone (MNTX) studies in opioid-treated patients with advanced illness and OIC, despite treatment with conventional laxatives. Baseline assessments included demographics, disease/treatment characteristics, and functional levels. Efficacy endpoints included rescue-free laxation (RFL) rates within 4 and 24 h, time to first RFL, pain score change, and adverse events (AEs) after a single MNTX dose or placebo.

RESULTS

The analysis included 281 patients receiving MNTX and 237 receiving placebo. Mean age was 66.2 years for MNTX and 65.8 for placebo; ∼50% were men. The most frequent primary diagnosis was cancer (MNTX = 70.5%; placebo = 66.2%) and most (∼98%) were receiving at least one laxative at baseline. RFL occurred in 61.4% vs. 16.0%, and 72.1% vs. 40.1% MNTX vs. placebo patients, within 4 and 24 h of the initial dose, respectively. Relative to placebo, MNTX use reduced the time to first RFL, with most MNTX-treated patients achieving RFL within 2 h. Baseline and posttreatment pain scores were similar (p = 0.9556 vs. placebo for current and worst pain change from baseline), demonstrating that MNTX did not negatively affect opioid analgesia. Most AEs were gastrointestinal related and dissipated by the second dose.

CONCLUSIONS

Methylnaltrexone provides early RFL without compromising analgesia in patients receiving chronic opioid therapy.

Auricular vagal nerve stimulation enhances gastrointestinal motility and improves interstitial cells of Cajal in rats treated with loperamide

BACKGROUND

Gastrointestinal (GI) motility disorders affect a large proportion of the population with limited treatment options. The aims of this study were to investigate the potential of a non-invasive method of auricular vagal nerve stimulation (aVNS) for treating GI dysmotility and to explore possible mechanisms involving slow waves and interstitial cells of Cajal (ICC).

METHODS

Normal rats were treated daily with loperamide for 1 week and then treated, while still on daily loperamide, with aVNS/Sham-aVNS for another 1 week. Gastric emptying (GE), small intestine transit (SIT), and GI slow waves were measured. The plasma level of pancreatic polypeptide (PP) and noradrenaline (NE) was assessed by ELISA. ICC in the gastric antrum were detected by immunohistochemistry.

KEY RESULTS

(a) aVNS significantly increased the percentage of normal GI slow waves (p < 0.05 for both fasting and postprandial states, vs. Sham-aVNS) and accelerated GE (p < 0.05, vs. Sham-aVNS) and SIT (p < 0.05, vs. Sham-aVNS) impaired by loperamide. (b) aVNS increased plasma PP (p < 0.01) and decreased plasma NE (p < 0.01), compared with Sham-aVNS. (c) Gastric ICC was decreased by loperamide (p < 0.01) but increased after aVNS (p < 0.01, vs. Sham aVNS).

CONCLUSIONS & INFERENCES

Loperamide induces upper GI dysmotility. aVNS accelerates upper GI transit and improving pace-making activity mediated via the ICC. Non-invasive aVNS may have a therapeutic potential for upper GI dysmotility.

Comparative Transcriptome Analysis Reveals Relationship among mRNAs, lncRNAs, and circRNAs of Slow Transit Constipation

Background

Slow transit constipation (STC) is characterized by persistent, infrequent, or incomplete defecation. Systematic analyses of mRNA, lncRNA, and circRNA expression profiling in STC provide insights to understand the molecular mechanisms of STC pathogenesis. The present study is aimed at observing the interaction of mRNAs, lncRNAs, and circRNAs by RNA sequencing in vivo of STC.

Methods

A rat model of STC was induced by loperamide. The expression profiles of both mRNAs and miRNAs were performed by RNA sequencing. Enrichment analyses of anomalous expressed mRNAs, lncRNAs, and circRNAs were performed in order to identify the related biological functions and pathologic pathways through the Gene Ontology (GO) database and Kyoto Encyclopedia of Genes and Genomes (KEGG) database.

Results

In total, 26435 mRNAs, 5703 lncRNAs, and 7708 circRNAs differentially expressed were identified between the two groups. The analyses of GO and KEGG show that (1) upregulated genes were enriched in a positive regulation of GTPase activity, cell migration, and protein binding and lipid binding and (2) GO annotations revealed that most trans-target mRNAs are involved in the regulation process of immune signal together with the proliferation and differentiation of immune cells. Additionally, the protein-protein interaction (PPI) network of differentially expressed (DE) mRNAs was constructed. Interestingly, all of the core lncRNAs and their coexpression mRNAs in this network are downregulated. Moreover, downregulated circRNAs have a set of target mRNAs related to immunoreaction, which was consistent with the overall tendency.

Conclusion

Our investigation enriches the STC transcriptome database and provides a preliminary exploration of novel candidate genes and avenues expression profiles in vivo. The dysregulation of mRNAs, lncRNAs, and circRNAs might contribute to the pathological processes during STC.

Management of Opioid-Induced Constipation and Bowel Dysfunction: Expert Opinion of an Italian Multidisciplinary Panel

The prescribing and use of opioid analgesics is increasing in Italy owing to a profusion in the number and types of opioid analgesic products available, and the increasing prevalence of conditions associated with severe pain, the latter being related to population aging. Herein we provide the expert opinion of an Italian multidisciplinary panel on the management of opioid-induced constipation (OIC) and bowel dysfunction. OIC and opioid-induced bowel dysfunction are well-recognised unwanted effects of treatment with opioid analgesics that can profoundly affect quality of life. OIC can be due to additional factors such as reduced mobility, a low-fibre diet, comorbidities, and concomitant medications. Fixed-dose combinations of opioids with mu (μ) opioid receptor antagonists, such as oxycodone/naloxone, have become available, but have limited utility in clinical practice because the individual components cannot be independently titrated, creating a risk of breakthrough pain as the dose is increased. A comprehensive prevention and management strategy for OIC should include interventions that aim to improve fibre and fluid intake, increase mobility or exercise, and restore bowel function without compromising pain control. Recommended first-line pharmacological treatment of OIC is with an osmotic laxative (preferably polyethylene glycol [macrogol]), or a stimulant laxative such as an anthraquinone. A second laxative with a complementary mechanism of action should be added in the event of an inadequate response. Second-line treatment with a peripherally acting μ opioid receptor antagonist (PAMORA), such as methylnaltrexone, naloxegol or naldemedine, should be considered in patients with OIC that has not responded to combination laxative treatment. Prokinetics or intestinal secretagogues, such as lubiprostone, may be appropriate in the third-line setting, but their use in OIC is off-label in Italy, and should therefore be restricted to settings such as specialist centres and clinical trials.

Auricular Vagal Nerve Stimulation Improves Constipation by Enhancing Colon Motility via the Central-Vagal Efferent Pathway in Opioid-Induced Constipated Rats

OBJECTIVES

Constipation and opioid-induced constipation (OIC) are common with limited treatment options. We investigated whether a noninvasive method of auricular vagal nerve stimulation (aVNS) could be used for treating OIC and explored its potential mechanisms and neural pathways in a rodent model of OIC.

MATERIALS AND METHODS

Sprague-Dawley were chronically implanted with one pair of auricular electrodes for aVNS. Sixteen rats were treated with loperamide for a week while another 16 rats received bilateral vagotomy, then randomly treated with aVNS or sham-aVNS for a week. In addition, eight normal rats were implanted with a polyethylene catheter in the proximal colon for assessing whole colon transit.

RESULTS

1) The number of fecal pellets and water content in feces increased after aVNS, compared with sham-aVNS. 2) aVNS accelerated colon transit and whole gut transit, compared with sham-aVNS. 3) In colon tissues, aVNS increased the protein expression of choline acetyltransferase, glial cell line-derived neurotrophic factor and the c-kit expression in myenteric interstitial cells of Cajal but decreased the protein expression of neural nitric oxide synthase (p < 0.05 for all, vs. sham-VNS). 4) The prokinetic effects of aVNS were abolished by both subdiaphragmatic vagotomy and atropine. 5) aVNS increased the c-fos expression in both nucleus tractus solitarius and dorsal motor nucleus of vagus, and increased vagal efferent activity (p < 0.05, vs. sham-VNS).

CONCLUSIONS

aVNS improves OIC by enhancing colon motility and restoring enteric neural functions mediated via the central and vagal efferent pathway.

Creating a bowel management plan for pediatric orthopaedic spine surgery patients

PURPOSE

Opioid-induced constipation is a common problem in patients who have undergone surgery. No standard gastrointestinal protocol exists to manage perioperative care in pediatric orthopaedic spinal fusion patients despite data which support the need for a bowel regimen while a patient is taking narcotics. At our institution, this group of patients often present to the emergency department with constipation and other gastrointestinal complaints. We developed a quality improvement initiative to create a standardized bowel management plan for pediatric patients undergoing orthopaedic spine surgery to decrease constipation, thus improving care, and minimizing unplanned visits.

METHODS

We developed a bowel management plan in collaboration with the gastroenterology team, created an Epic Smart Phrase for discharge instructions to enhance compliance, and created and dispersed informational communication on changes to constipation management. We monitored compliance, emergency department visits, and re-admissions.

RESULTS

Compliance with the bowel management plan, including inpatient medication prescribing and discharge "at-home" education, has increased to a mean of 93%. Emergency Department (ED) visits or re-admissions for constipation were reduced from a baseline mean of 1 in every 11 cases, to 1 in every 184 cases. Our institution sustained more than 2 years without an ED visit or readmission related to constipation in this patient population after the bowel management plan was in place.

CONCLUSION

A bowel management plan can be used in the care of pediatric spinal fusion patients to increase patient safety, decrease healthcare burden, and improve care. This project not only increased awareness of post-surgical gastrointestinal symptoms and opioid side effects, but also decreased post-operative emergency department visits and re-admissions related to constipation.

LEVEL OF EVIDENCE

III, case control study.

Efficacy and Safety of Peripherally Acting Mu-Opioid Receptor Antagonists for the Treatment of Opioid-Induced Constipation: A Bayesian Network Meta-analysis

OBJECTIVE

To assess the efficacy and safety of peripherally acting mu-opioid receptor antagonists (PAMORAs) for the treatment of opioid-induced constipation (OIC).

METHODS

Randomized controlled trials (RCTs) were searched for OIC therapy comparing PAMORAs with placebo. Both a pairwise and network meta-analysis were performed. The surface under the cumulative ranking area (SUCRA) was used to determine the efficacy and safety of OIC treatment using different PAMORAs.

RESULTS

The primary target outcome was a response that achieves an average of three or more bowel movements (BMs) per week. In the network meta-analysis, four PAMORAs (naldemedine, naloxone, methylnaltrexone, and alvimopan) showed a better BM response than the placebo. Naldemedine was ranked first (odds ratio [OR] = 2.8, 95% credible interval [CrI] = 2-4.5, SUCRA = 89.42%), followed by naloxone (OR = 2.9, 95% CrI = 1.6-5.3, SUCRA = 87.44%), alvimopan (OR = 2.2, 95% CrI = 1.3-3.5, SUCRA = 68.02%), and methylnaltrexone (OR = 1.7, 95% CrI = 1.0-2.8, SUCRA = 46.09%). There were no significant differences in safety found between the PAMORAs and the placebo.

CONCLUSIONS

We found that PAMORAs are effective and can be safely used for the treatment of OIC. In network meta-analysis, naldemedine and naloxone appear to be the most effective PAMORAs for the treatment of OIC.

What to Do and What Not to Do in the Management of Opioid-Induced Constipation: A Choosing Wisely Report

Introduction

Despite the essential utility of opioids for the clinical management of pain, opioid-induced constipation (OIC) remains an important obstacle in clinical practice. In patients, OIC hinders treatment compliance and has negative effects on quality of life. From a clinician perspective, the diagnosis and management of OIC are hampered by the absence of a clear, universal diagnostic definition across disciplines and a lack of standardization in OIC treatment and assessment.

Methods

A multidisciplinary panel of physician experts who treat OIC was assembled to identify a list of ten corrective actions—five “things to do” and five “things not to do”—for the diagnosis and management of OIC, utilizing the Choosing Wisely methodology.

Results

The final list of corrective actions to improve the diagnosis and clinical management of OIC emphasized a need for: (i) better physician and patient education regarding OIC; (ii) systematic use of diagnostically validated approaches to OIC diagnosis and assessment (i.e., Rome IV criteria and Bristol Stool Scale, respectively) across various medical contexts; and (iii) awareness about appropriate, evidence-based treatments for OIC including available peripheral mu-opioid receptor antagonists (PAMORAs).

Conclusions

Physicians who prescribe long-term opioids should be forthcoming with patients about the possibility of OIC and be adequately versed in the most recent guideline recommendations for its management.

An exploration of attitudes and preferences towards medications among healthcare providers and persons with spinal cord injury/dysfunction: a qualitative comparison

PURPOSE

To compare the attitudes and preferences of persons with spinal cord injury/dysfunction (SCI/D) and healthcare providers regarding prescription medications, over-the-counter medications, and natural health products (NHPs).

MATERIALS AND METHODS

A qualitative study involving semi-structured interviews with healthcare providers (n = 32) and persons with SCI/D (n = 19) in Canada. Inductive descriptive and interpretive analyses were conducted using data display matrices and a constant comparative approach.

RESULTS

Participants described differing perceptions of therapeutic benefits based on medication type, with shared attitudes about the therapeutic benefits of prescription medications and differing views about the effectiveness of NHPs. Despite the perceived effectiveness of prescription medications, persons with SCI/D preferred to avoid them due to concerns about side effects, safety, and stigma. Persons with SCI/D were often concerned about the long-term safety of prescription medications, whereas providers focused more on medication-related addictions. Participants discussed stigma relating to prescription medications, NHPs, and medicinal marijuana.

CONCLUSION

Healthcare providers and persons with SCI/D described different attitudes about and preferences for pharmacotherapeutic products, contributing to challenges in optimizing medication management. Strategies to improve medication management include shared decision-making to incorporate patient preferences into care plans and explicit discussions about long-term medication safety. Further, steps are needed to combat the stigma associated with medication use.Implications for rehabilitationFollowing a person-centered approach to shared decision-making, prescribers should initiate explicit conversations about patient medication preferences, short and long-term prescription medication side effects, and alternative treatment options.Regarding prescription medication safety, persons with spinal cord injury/dysfunction focused on the long term impact of medications, while providers focused on medication-related addictions, highlighting a disconnect that should be discussed during initiation, continuation, or discontinuation of a medication.Providers should be mindful of the stigma associated with taking multiple prescription medications, including medicinal marijuana, as well as the stigma associated with over-the-counter medications and natural health products.Providers could benefit from education about spinal cord injury/dysfunction-specific prescription medications and could benefit from increased education about natural health products.

Impact of opioid use on patients undergoing screening colonoscopy according to the quality of bowel preparation

Aims

Constipation associated with opioid therapy for chronic pain may negatively impact colonoscopy success. This retrospective, observational study using administrative data and electronic medical records evaluated the impact of opioid use on colonoscopy outcomes.

Methods and Results

Procedural codes were used to identify patients who had a screening colonoscopy at two Henry Ford Health System centers (January 2015–December 2016). All patients had completed a standard uniform bowel preparation protocol. Medication orders and filled prescriptions were used to identify patients with a history of opioid use during the 28 days preprocedure (exposed) and a matched random sample of presumptive opioid nonusers (unexposed). Electronic medical records were reviewed for colonoscopy procedure data and outcomes.

The exposed and unexposed groups included 964 and 1054 patients, respectively. Inadequate bowel preparation was significantly more common in the exposed versus unexposed group (18.5% vs 12.7%; P < 0.001). In the exposed and unexposed groups, 97.1 and 98.0% of colonoscopy procedures were completed, respectively (P = nonsignificant). Total procedure time was slightly increased for the exposed versus unexposed group (23.8 vs 22.5 min; P = 0.039). Polyp identification and cancer diagnosis were similar between groups. Prolonged sedation occurred in three patients in the exposed group and none in the unexposed group. Procedural complications were rare, but the incidence was significantly greater in the exposed versus unexposed group (1.3% vs 0.2%; P < 0.01).

Conclusions

Opioid exposure was associated with significant reductions in the quality of preprocedure bowel preparation and an increased risk of complications in patients undergoing colonoscopy.

Spinal cord injury/dysfunction and medication management: a qualitative study exploring the experiences of community-dwelling adults in Ontario, Canada

Purpose: To explore the attitudes, beliefs and experiences pertaining to the management of prescribed and unprescribed medications among community-dwelling adults with spinal cord injury/dysfunction (SCI/D) in Ontario, Canada.Materials and Methods: In-depth semi-structured interviews were conducted by telephone. Each interview was audio-recorded, transcribed verbatim and analyzed using inductive thematic analysis.Results: Of the 19 participants, 11 were male and 8 were female, with an age range from 36 to 76 years; 14 participants had traumatic SCI and 5 had non-traumatic spinal cord dysfunction. All but three participants were taking five or more medications, including prescription medications, over-the-counter medications and natural health products. The three main themes identified were: disruptive nature of medications, fear of negative outcomes and self-management: playing a critical role.Conclusions: Medication management is a complex, multifaceted and non-linear process. Persons with SCI/D described experiences with medication-taking that are not well understood by current medication management frameworks. Thus, it is essential to broaden our lens and situate persons with SCI/D medication-taking experiences within self-management frameworks to allow for a more comprehensive and reflective understanding of their experiences. Based on the findings from this study, recommendations for future research, practice and policy have been suggested.IMPLICATIONS FOR REHABILITATIONPersons with spinal cord injury/dysfunction identified numerous challenges and concerns with medication use post-injury.Educational medication management programs should be implemented post-discharge to improve the state of knowledge around medications (indication, side effects, strategies for taking medications) and how to optimize medication management.In order to optimize experiences and outcomes, there is a need for explicit and ongoing discussions around medication management between persons with spinal cord injury/dysfunction and their healthcare providers.

Critical evaluation of animal models of visceral pain for therapeutics development: A focus on irritable bowel syndrome

The classification of chronic visceral pain is complex, resulting from persistent inflammation, vascular (ischemic) mechanisms, cancer, obstruction or distension, traction or compression, and combined mechanisms, as well as unexplained functional mechanisms. Despite the prevalence, treatment options for chronic visceral pain are limited. Given this unmet clinical need, the development of novel analgesic agents, with defined targets derived from preclinical studies, is urgently needed. While various animal models have played an important role in our understanding of visceral pain, our knowledge is far from complete. Due to the complexity of visceral pain, this document will focus on chronic abdominal pain, which is the major complaint in patients with disorders of the gut-brain interaction, also referred to as functional gastrointestinal disorders, such as irritable bowel syndrome (IBS). Models for IBS are faced with challenges including a complex clinical phenotype, which is comorbid with other conditions including anxiety, depression, painful bladder syndrome, and chronic pelvic pain. Based upon the multifactorial nature of IBS with complicated interactions between biological, psychological, and sociological variables, no single experimental model recapitulates all the symptoms of IBS. This position paper will contextualize chronic visceral pain using the example of IBS and focus on its pathophysiology while providing a critical review of current animal models that are most relevant, robust, and reliable in which to screen promising therapeutics to alleviate visceral pain and delineate the gaps and challenges with these models. We will also highlight, prioritize, and come to a consensus on the models with the highest face/construct validity.

Rates of appropriate laxative prophylaxis for opioid-induced constipation in veterans with lung cancer: a retrospective cohort study

PURPOSE

Opioid-induced constipation (OIC) is the most common side effect in patient-prescribed opioids for cancer pain treatment. Current guidelines recommend routine prescription of a laxative for preventing OIC in all patients prescribed an opioid unless a contraindication exists. We determined patterns of prescription of laxative agents in patients with lung cancer initiating opioids.

METHODS

We performed a retrospective cohort study evaluating the prescription of laxatives for OIC to adult patients with incident lung cancer seen in the Veteran's Affairs (VA) system, between January 1, 2003, and December 31, 2016. Exposure to laxative agents was categorized as follows: none, docusate monotherapy, docusate plus another laxative, and other laxatives only. Prevalence of OIC prophylaxis was analyzed using descriptive statistics. Linear regression was performed to identify time trends in the prescription of OIC prophylaxis.

RESULTS

Overall, 130,990 individuals were included in the analysis. Of these, 87% of patients received inadequate prophylaxis (75% no prophylaxis and 12% docusate alone), while 5% received OIC prophylaxis with the unnecessary addition of docusate to another laxative. Through the study period, laxative prescription significantly decreased, while all other categories of OIC prophylaxis were unchanged. We noted an inverse relationship with OIC prophylaxis and likelihood of a diagnosis of constipation at 3 and 6 months.

CONCLUSIONS

In this study of veterans with lung cancer, almost 90% received inadequate or inappropriate OIC prophylaxis. Efforts to educate physicians and patients to promote appropriate OIC prophylaxis in combination with systems-level changes are warranted.

Patient and provider differences in the treatment of opioid-induced constipation: a qualitative study

BACKGROUND

Patients using opioids to treat chronic non-cancer pain often experience side effects that may affect health-related quality of life (HRQOL). These side effects include opioid-induced constipation (OIC), sedation, dizziness, and nausea. OIC can significantly affect HRQOL for patients on a daily basis. However, it is not well understood whether patients and clinicians view OIC management similarly.

AIMS

In this study, we sought to elucidate the decision-making process around managing OIC by assessing patient and provider treatment preferences, experiences, and communication regarding this condition.

METHODS

We conducted semi-structured interviews with 33 clinicians, and held three focus groups with patients who were currently using or had used opioids for chronic non-cancer pain. We then analyzed transcribed interviews using descriptive qualitative methods based on grounded theory methodology.

RESULTS

Clinicians recognized OIC as a concern but prioritized pain management over constipation. They focused on medication-based treatments for OIC, but also recommended lifestyle changes (e.g., diet) and reducing opioids to relieve symptoms. Patients reported using over-the-counter treatments, but the majority focused on diet-related constipation management. Patients reported not receiving adequate information from clinicians about OIC and relevant treatments. Cost of treatment was a major concern for both patients and clinicians.

CONCLUSIONS

Assessing experiences with and preferences for OIC treatment, including cost, ease of access, and side effects, could improve patient-provider communication and HRQOL. Quality improvement efforts can target uncovered misalignments between patients and clinicians to improve communication about opioid medication adverse effects and relevant treatment options, which may help improve quality of life for patients with chronic pain.

Electroacupuncture via chronically implanted electrodes improves gastrointestinal motility by balancing sympathovagal activities in a rat model of constipation

Electroacupuncture (EA) has been reported for treating constipation in clinical studies. However, little is known of the possible mechanisms involved in the prokinetic effect of EA. The aim of this study was to investigate the effects and underlying autonomic mechanisms of EA via chronically implanted electrodes for constipation in rat induced by Loperamide (Lop). Lop was given to regular rats to induce constipation. EA was performed via a pair of electrodes chronically implanted at bilateral acupoint ST-36. Feces characteristics, gastric emptying, small intestinal transit, distal colon transit time (dCTT), and whole gut transit time (WGTT) were measured in various sessions with EA or sham EA in rats with constipation induced by Lop. Heart rate variability (HRV) derived from the electrocardiogram was analyzed to evaluate autonomic functions. The number of fecal pellets was reduced by 27% with Lop (P < 0.01) and normalized by 7-day EA. Similar results were also observed in pellet weight. In normal rats compared with sham EA, EA shortened dCTT by 74% (P < 0.05 vs. sham EA), increased small intestinal transit by 28% (P < 0.01) and gastric emptying by 27% (P < 0.05), and accelerated whole gut transit by 14% (P < 0.05). In Lop-treated rats, the dCTT and WGTT were prolonged by Lop and normalized by EA. Lop significantly decreased vagal activity and increased sympathetic nerve activity; however, EA reversed these effects. EA at ST-36 via chronically implanted electrodes improves Lop-induced constipation by enhancing GI motility via the autonomic mechanisms. NEW & NOTEWORTHY The findings of the present study suggest that the proposed electroacupuncture (EA) may have great therapeutic potential for treating patients with opioid-induced constipation. It was demonstrated that EA at ST-36 improved transit of every organ along the gut mediated via the autonomic mechanisms in normal rats and rats with Lop-induced constipation. It is advised to administrate EA daily instead of two or three times weekly as reported in most of the clinical studies.

A Randomized, Multicenter, Prospective, Crossover, Open-Label Study of Factors Associated With Patient Preferences for Naloxegol or PEG 3350 for Opioid-Induced Constipation

OBJECTIVES

To determine patient preference for treating opioid-induced constipation (OIC) using naloxegol or polyethylene glycol (PEG) 3350 in patients receiving opioids for noncancer pain.

METHODS

This crossover study included two 2-week active treatment periods, each preceded by a 1-week washout period (NCT03060512). Individuals with baseline Bowel Function Index scores ≥30 were randomized to 1 of 2 treatment sequences (naloxegol/PEG 3350 or PEG 3350/naloxegol). Patient preference (primary end point) was measured at the end of the second treatment period.

RESULTS

Of 276 patients randomized, 246 completed both treatment periods and reported preference (per protocol). Similar proportions of patients reported overall preference for naloxegol (50.4%) or PEG 3350 (48.0%; P = 0.92); 1.6% reported no preference. Medication characteristics influencing preference were similar for both treatments, except convenience and working quickly, which were strong influences of preference for higher proportions of patients preferring naloxegol (69.9% and 39.0%, respectively) vs those preferring PEG 3350 (29.9% and 27.4%, respectively). Patients aged <50 years or receiving laxatives within the previous 2 weeks generally preferred naloxegol. Changes from baseline in overall Bowel Function Index and Patient Global Impression of Change scores were similar between treatments, but analyses according to treatment preference revealed clinical improvement aligned with reported preference. Safety profiles were generally consistent with known medication profiles.

CONCLUSIONS

Almost equal proportions of patients with OIC reported similar preference for daily naloxegol or PEG 3350 treatment, and their preference was generally supported by clinically relevant and measurable improvements in OIC symptoms.

Methylnaltrexone-Associated Bowel Perforation in Postoperative Opioid-Induced Constipation and Ogilvie Syndrome: A Case Report

Pain management with opioids is often limited by medication side effects. One of the most common and distressing side effects is opioid-induced constipation (OIC), a syndrome that is now getting significant national attention. We report the case of an opioid-dependent 56-year-old man who underwent lumbar decompression for spinal stenosis. Postoperatively, he developed OIC and Ogilvie syndrome, then following treatment with methylnaltrexone experienced an acute bowel perforation. We briefly review the recommended management of OIC as well as indications and contraindications of methylnaltrexone and similar new medications.

Opioid-induced constipation: a narrative review of therapeutic options in clinical management

Pain therapy often entails gastrointestinal adverse events. While opioids are effective drugs for pain relief, the incidence of opioid-induced constipation (OIC) varies greatly from 15% to as high as 81%. This can lead to a significant impairment in quality of life, often resulting in discontinuation of opioid therapy. In this regard, a good doctor-patient relationship is especially pivotal when initiating opioid therapy. In addition to a detailed history of bowel habits, patient education regarding the possible gastrointestinal side effects of the drugs is crucial. In addition, the bowel function must be regularly evaluated for the entire duration of treatment with opioids. Furthermore, if the patient has preexisting constipation that is well under control, continuation of that treatment is important. In the absence of such history, general recommendations should include sufficient fluid intake, physical activity, and regular intake of dietary fiber. In patients of OIC with ongoing opioid therapy, the necessity of opioid use should be critically reevaluated in terms of an with acceptable quality of life, particularly in cases of non-cancer pain. If opioids must be continued, lowering the dose may help, as well as changing the type of opioid. If these measures do not suffice, the next step for persistent OIC is the administration of laxatives. If these are ineffective as well, treatment with peripherally active μ-opioid receptor antagonists should be considered. Enemas and irrigation are emergency measures, often used as a last resort.

Clinical Overview and Considerations for the Management of Opioid-induced Constipation in Patients With Chronic Noncancer Pain

OBJECTIVES

Opioid analgesics may be associated with chronic adverse effects, such as opioid-induced constipation (OIC). Available and emerging prescription medications for OIC in patients with chronic noncancer pain are described, including concerns and challenges associated with OIC management.

METHODS

Narrative review.

RESULTS

OIC is characterized by a change in bowel habits and defecation patterns that occurs when initiating opioid therapy and is associated with reduced bowel frequency, straining, sensation of incomplete evacuation, and/or patient distress related to bowel habits. Prescription medications are indicated when OIC persists despite conservative approaches (eg, increased fiber and fluid intake, exercise, over-the-counter laxatives and stool softeners). Phase 3 studies have demonstrated the efficacy of peripherally acting µ-opioid receptor antagonists (PAMORA; methylnaltrexone, naloxegol, naldemedine), and a chloride channel activator (lubiprostone) for improving OIC in patients with chronic noncancer pain. Although head-to-head studies are lacking, a meta-analysis demonstrated that μ-opioid receptor antagonists were more effective than placebo for the treatment of OIC. The most common adverse effects associated with prescription medications for OIC are gastrointestinal related (eg, nausea, diarrhea, abdominal pain, or distention), with most being mild or moderate in severity. Therapy currently in development for OIC includes the PAMORA axelopran.

DISCUSSION

Health care providers should be aware of this complication in patients receiving opioids and should monitor and address constipation-related symptoms to optimize pain management and improve patient quality of life.

Safety of oral methylnaltrexone for opioid-induced constipation in patients with chronic noncancer pain

Purpose

Oral methylnaltrexone was shown to be effective in treating opioid-induced constipation (OIC) in patients with chronic noncancer pain in a Phase III randomized controlled trial. This report provides a detailed safety analysis from that study.

Methods

Adults (n=803) with chronic noncancer pain for ≥2 months and confirmed OIC while receiving opioid doses ≥50 mg morphine equivalent per day for ≥14 days were randomized 1:1:1:1 to oral methylnaltrexone (150, 300, or 450 mg) or placebo once daily for 4 weeks, followed by as-needed use for 8 weeks. Safety was evaluated by examining treatment-emergent adverse events (TEAEs), clinical laboratory parameters, vital signs, electrocardiography, rescue-laxative and opioid use, Objective Opioid Withdrawal Scale (OOWS) and Subjective Opioid Withdrawal Scale (SOWS), and pain-intensity scores.

Results

TEAEs occurred at a similar incidence in the methylnaltrexone groups (59.0%) and placebo group (63.0%). The most common TEAEs with methylnaltrexone were abdominal pain (8.0% vs 8.5% with placebo), nausea (6.8% vs 9.0%), and diarrhea (6.0% vs 3.5%). Cardiac-related TEAEs occurred in 1.8% and 1.0% of patients, respectively, and no major adverse cardiovascular events were reported. No patient had a cluster of TEAEs associated with opioid withdrawal after excluding gastrointestinal TEAEs. Changes in laboratory parameters, vital signs, and electrocardiography were generally small and similar across treatment groups. Rescue-laxative use was more common with placebo than methylnaltrexone 450 mg (6.20% vs 4.27% of study days, P=0.024). Changes in opioid dose, OOWS and SOWS scores, and pain-intensity scores during treatment were minimal.

Conclusion

Oral methylnaltrexone had a safety profile comparable with placebo in the treatment of OIC in patients with chronic noncancer pain, with no evidence of cardiac toxicity or opioid withdrawal.

Oral methylnaltrexone does not negatively impact analgesia in patients with opioid-induced constipation and chronic noncancer pain

Purpose

An oral formulation of methylnaltrexone has been developed for treating opioid-induced constipation (OIC). This manuscript examines the impact of oral methylnaltrexone, a peripherally acting µ-opioid receptor antagonist, on opioid analgesia.

Methods

This Phase III, randomized, double-blind, placebo-controlled trial, evaluated changes in pain intensity scores (0= no pain to 10= worst possible pain) and opioid use in adults with chronic noncancer pain. Patients taking ≥50 mg/day oral morphine equivalent dose (MED) for ≥14 days before screening with less than three rescue-free bowel movements/week received oral methylnaltrexone 150 mg/day (n=201), 300 mg/day (n=201), 450 mg/day (n=200), or placebo (n=201) once daily for 4 weeks followed by 8 weeks of oral methylnaltrexone as needed.

Results

The primary condition requiring opioid use was back pain (68.2% of 803 patients). Baseline pain intensity scores were similar among treatment groups (mean range, 6.2–6.4) and remained stable throughout the 4-week double-blind (mean range, 6.1–6.5) and 8-week as needed (mean range, 6.3–6.5) periods. Baseline mean MED was comparable between oral methylnaltrexone 150 mg (200.0 mg/day), methylnaltrexone 450 mg (218.0 mg/day), and placebo (209.7 mg/day), but was slightly higher in the oral methylnaltrexone 300-mg group (252.6 mg/day). Nonsignificant, minimal changes in mean MED were observed after 4 weeks of treatment (214.5–235.6 mg/day) and at the end of the as needed phase (202.3–234.9 mg/day). The percentage of patients who initiated new opioid medications during the 4-week, once-daily dosing period was generally similar among the oral methylnaltrexone 150-mg, 300-mg, and 450-mg groups (44.8%, 43.3%, and 35.0%, respectively), the oral methylnaltrexone combined group (41.0%), and the placebo group (39.8%). The most common newly initiated opioid medications during this once-daily period were oxycodone (oral methylnaltrexone groups combined, 14.6%; placebo, 12.4%) and morphine (oral methylnaltrexone combined, 10.1%; placebo, 7.0%).

Conclusion

Oral methylnaltrexone does not elicit opioid withdrawal or interfere with opioid analgesia.

Neer Award 2018: the effect of preoperative education on opioid consumption in patients undergoing arthroscopic rotator cuff repair: a prospective, randomized clinical trial

BACKGROUND

Opioids are commonly administered for the treatment of acute and chronic pain symptoms. The current health care system is struggling to deal with increasing medication abuse and rising mortality rates from overdose. Preoperative patient-targeted education on opioid use is an avenue yet to be explored. The purpose of the study was to determine whether preoperative narcotics education reduces consumption after arthroscopic rotator cuff repair (ARCR).

METHODS

Patients undergoing primary ARCR at our institution were randomized to receiving opioid-related preoperative education or not. Patients filled out preoperative questionnaires detailing complete medical history and visual analog scale (VAS) for pain. Patients completed questionnaires regarding their opioid consumption and pain at their 2-week, 6-week, and 3-month follow-up.

RESULTS

The study enrolled 140 patients. Patients in the study group consumed significantly less narcotics than the control group at the 3-month follow-up. Patients in the education group were 2.2 times more likely to discontinue narcotic use by the end of follow-up (odds ratio, 2.19; P = .03). In addition, patients with a history of preoperative narcotic use that were in the education group were 6.8 times more likely to discontinue narcotics by the end of follow-up (odds ratio, 6.8; P = .008).

DISCUSSION/CONCLUSIONS

The findings of this study determined that preoperative education intervention significantly decreased the number of narcotic pills consumed at 3 months after ARCR. In addition, education resulted in earlier cessation of opioids; therefore, directed patient education can help alleviate the current opioid epidemic.