Lubiprostone in constipation: clinical evidence and place in therapy

Potential Therapeutic Strategies in the Treatment of Metabolic-Associated Fatty Liver Disease

Metabolic-associated Fatty Liver Disease is one of the outstanding challenges in gastroenterology. The increasing incidence of the disease is undoubtedly connected with the ongoing obesity pandemic. The lack of specific symptoms in the early phases and the grave complications of the disease require an active approach to prompt diagnosis and treatment. Therapeutic lifestyle changes should be introduced in a great majority of patients; but, in many cases, the adherence is not satisfactory. There is a great need for an effective pharmacological therapy for Metabolic-Associated Fatty Liver Disease, especially before the onset of steatohepatitis. Currently, there are no specific recommendations on the selection of drugs to treat liver steatosis and prevent patients from progression toward more advanced stages (steatohepatitis, cirrhosis, and cancer). Therefore, in this Review, we provide data on the clinical efficacy of therapeutic interventions that might improve the course of Metabolic-Associated Fatty Liver Disease. These include the drugs used in the treatment of obesity and hyperlipidemias, as well as affecting the gut microbiota and endocrine system, and other experimental approaches, including functional foods. Finally, we provide advice on the selection of drugs for patients with concomitant Metabolic-Associated Fatty Liver Disease.

Lubiprostone plus polyethylene glycol electrolyte lavage solution (PEG-ELS) versus PEG-ELS for bowel preparation in chronic constipation: a randomized controlled trial

Colonoscopy is considered the standard procedure for early detection and prevention of colorectal cancer. Adequate bowel cleansing is an important determinant of the efficacy of colonoscopy screening. Currently, there is no standard method of bowel preparation for patients with chronic constipation. The aim was to access the rate of adequate bowel cleansing achieved using split-dose polyethylene glycol electrolyte lavage solution (PEG-ELS) plus lubiprostone in comparison with split-dose PEG-ELS alone. A single-centre, endoscopist-blinded, randomized controlled trial was conducted. Seventy-eight constipated patients aged 18-75 years who were indicated for colonoscopy in the gastroenterology unit of Srinagarind Hospital, Khon Kaen University, between February 2020 and February 2021 were randomly allocated to receive either split-dose PEG-ELS in combination with lubiprostone (N = 39) or split-dose PEG-ELS alone (N = 39) before colonoscopy. Adequate bowel cleansing was defined as an Ottawa bowel preparation score ≤ 7. The rate of adequate bowel cleansing was comparable between the PEG-ELS plus lubiprostone group and the PEG-ELS alone group (50% vs. 52.9%, p value = 0.81) with a relative risk of 1.13 (95% CI = 0.43-2.91). There were no significant differences in adenoma detection rate (41.2% vs. 35.3%, p value = 0.62), adverse events, acceptance, compliance, or patient satisfaction between the 2 groups. No additional benefit to successful bowel preparation was achieved by the combination of lubiprostone and PEG-ELS in chronic constipation patients undergoing colonoscopy.

Alleviation of cholestatic liver injury and intestinal permeability by lubiprostone treatment in bile duct ligated rats: role of intestinal FXR and tight junction proteins claudin-1, claudin-2, and occludin

Gut barrier disintegrity and endotoxin translocation to the liver and systemic circulation are serious clinical complications associated with the stoppage of intestinal bile flow. There is no precise pharmacological option to prevent increased intestinal permeability after bile duct ligation (BDL). Lubiprostone, a chloride channel-2 agonist, has been shown to accelerate restoration of epithelial barrier dysfunction caused by injury, but the exact mechanisms underlying the beneficial effects of lubiprostone on intestine barrier integrity remain unknown. Here, we assessed the beneficial effect of lubiprostone on cholestasis caused by BDL and relevant mechanisms. Male rats were subjected to BDL for 21 days. Seven days after BDL induction, lubiprostone was administered twice daily (10 µg/kg of body weight). Intestinal permeability was assessed through measurements of serum lipopolysaccharide (LPS) concentration. Real-time PCR was conducted to assess expression of intestinal claudin-1 occludin and FXR genes, which are important in preserving the intestinal epithelial barrier integrity, as well as claudin-2 being involved in a leaky gut barrier. Histopathological alterations were also monitored for liver injury. Lubiprostone significantly decreased BDL-induced systemic LPS elevation in rats. BDL induced a significant reduction in FXR, occludin, and claudin-1 genes expression, while increased claudin-2 expression in rat colon. Treatment with lubiprostone significantly restored expression of these genes to the control values. BDL also increased the level of hepatic enzymes ALT, ALP, AST, and total bilirubin, while lubiprostone could preserve the hepatic enzymes and total bilirubin in the treated BDL rats. Lubiprostone also caused a significant reduction in BDL-induced liver fibrosis and intestinal damage in rats. Our results suggest that lubiprostone favorably prevents BDL-induced alterations in intestinal epithelial barrier integrity possibly via modulating intestinal FXRs and tight junction gene expression.

Analysis of the impact on efficacy of lubiprostone dose reduction to manage adverse events in the treatment of chronic constipation in Japan

OBJECTIVE

To compare outcomes between two doses of lubiprostone in patients with chronic constipation (CC), to assess whether dose reduction affects efficacy.

METHODS

This open-label exploratory study involved 146 patients with CC treated initially with lubiprostone 24 mcg twice daily for a planned duration of 4 weeks. Patients who experienced adverse events (AEs) had their dose reduced to 12 mcg twice daily (for 4 weeks).

RESULTS

Lubiprostone dose was unchanged in 104 patients and reduced due to AEs in 42 patients. Significant differences in the mean number of bowel movements per week favored the dose-reduced group at Week 1 and end of follow-up. No between-group differences were observed over time for mean number of days per week with bowel movements or mean Bristol Stool Form Scale scores. Symptoms of abdominal bloating, strained defecation, and sensation of incomplete evacuation improved in both groups. Before dose reduction, nausea was reported by 64.3% and diarrhea by 45.2% of patients in the dose-reduced group; after dose reduction, no patients reported nausea and one patient reported diarrhea.

CONCLUSION

Dose reduction of lubiprostone reduced the incidence of AEs, with no compromise to efficacy, and may be a suitable approach for patients who develop AEs during treatment.

Lubiprostone is non-selective activator of cAMP-gated ion channels and Clc-2 has a minor role in its prosecretory effect in intestinal epithelial cells

Loss of prosecretory Cl- channel CFTR activity is considered as the key cause of gastrointestinal disorders in cystic fibrosis including constipation and meconium ileus. Clc-2 is proposed as an alternative Cl- channel in intestinal epithelia that can compensate for CFTR loss-of-function. Lubiprostone is an FDA-approved drug with Clc-2 activation as its presumed mechanism of action. However, relative contribution of Clc-2 in intestinal Cl- secretion and the mechanism of action of lubiprostone remain controversial due to lack of selective Clc-2 inhibitors. Using recently identified selective Clc-2 inhibitor AK-42, we characterized the roles of Clc-2 in Cl- secretion in human intestinal epithelial T84 cells. Clc-2 inhibitor AK-42 had minimal (15%) inhibitory effect on secretory short-circuit current (Isc) induced by cAMP agonists, where subsequently applied CFTR inhibitor (CFTRinh-172) caused 2-3 fold greater inhibition. Similarly, AK-42 inhibited lubiprostone-induced secretory Isc by 20%, whereas CFTRinh-172 caused 2-3 fold greater inhibition. In addition to increasing CFTR and Clc-2-mediated apical Cl- conductance, lubiprostone increased basolateral membrane K+ conductance, which was completely reversed by cAMP-activated K+ channel inhibitor BaCl2 All components of lubiprostone-induced secretion (Clc-2, CFTR and K+ channels) were inhibited by ~65% with the extracellular Ca2+-sensing receptor (CaSR) activator cinacalcet that stimulates cAMP hydrolysis. Lastly, EP4 prostaglandin receptor inhibitor GW627368 pretreatment inhibited lubiprostone-induced secretion by 40% without any effect on forskolin response. Our findings suggest that Clc-2 has minor role in cAMP-induced intestinal Cl- secretion; and lubiprostone is not a selective Clc-2 activator, but general activator of cAMP-gated ion channels in human intestinal epithelial cells. Significance Statement Cl- channel Clc-2 activation is the proposed mechanism of action of the FDA-approved constipation drug lubiprostone. Using first-in-class selective Clc-2 inhibitor AK-42, we showed that Clc-2 has minor contribution in intestinal Cl- secretion induced by lubiprostone and cAMP agonists. We also found that lubiprostone is a general activator of cAMP-gated ion channels in human intestinal epithelial cells (via EP4 receptors). Our findings clarify the roles of Clc-2 in intestinal Cl- secretion and elucidate the mechanism of action of approved-drug lubiprostone.

One Size Does Not Fit All: The Past, Present and Future of Cystic Fibrosis Causal Therapies

Cystic fibrosis (CF) is the most common monogenic disorder, caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Over the last 30 years, tremendous progress has been made in understanding the molecular basis of CF and the development of treatments that target the underlying defects in CF. Currently, a highly effective CFTR modulator treatment (Kalydeco™/Trikafta™) is available for 90% of people with CF. In this review, we will give an extensive overview of past and ongoing efforts in the development of therapies targeting the molecular defects in CF. We will discuss strategies targeting the CFTR protein (i.e., CFTR modulators such as correctors and potentiators), its cellular environment (i.e., proteostasis modulation, stabilization at the plasma membrane), the CFTR mRNA (i.e., amplifiers, nonsense mediated mRNA decay suppressors, translational readthrough inducing drugs) or the CFTR gene (gene therapies). Finally, we will focus on how these efforts can be applied to the 15% of people with CF for whom no causal therapy is available yet.

Review of the Safety Profiles of Laxatives in Pregnant Women

Chronic constipation is one of the most common complaints seen in the gastroenterology clinic and is particularly prevalent in women. Women who become pregnant may suffer from existing constipation or develop constipation de novo. A thorough understanding of the safety of laxative therapies during pregnancy and the postpartum period is essential to successfully treating these women. Current understanding of the safety of both over the counter and prescription laxatives has not been adequately evaluated. In this article we provide an updated and comprehensive review of the safety profiles of laxatives that are currently used for the treatment of chronic constipation to aid the clinician in risk-benefit discussions with women who are currently or planning to become pregnant.

Evaluating lubiprostone for effective bowel preparation before colonoscopy

Background

Colon preparation is a fundamental step for performing a successful colonoscopy. We aimed to evaluate the effectiveness of administering lubiprostone (LB) added to a single dose of oral polyethylene glycol (PEG) solution in achieving satisfactory colon cleanliness and decreasing the side effects.

Results

One-hundred percent of the control group patients reported that the experienced taste was worse than expected, while in the intervention group half of the patients (50%) said that the taste was natural and 48% experienced taste worse than expected (p<0.0001). Regarding Boston bowel preparation scale (BBPS), there was a significant difference in the overall Boston scale (p=0.02) with more efficacy in the intervention group as 66% of patients in the intervention group had good bowel preparation (5–7) and 24% excellent preparation (8–9). On the other hand, the overall Boston scale in the control group showed that 54% of patients were between 5 and 7, and only 16% of patients had overall Boston scale 8–9. In terms of the side effects of the preparation in both arms, the majority of cases in the intervention arm did not complain of any side effects (78%), while the majority of the complaints were vomiting in 16% of the intervention cases.

Conclusion

The current evidence suggested that adding LB to the colon preparation significantly improved the tolerability and efficacy.

Safety of Lubiprostone in Pediatric Patients With Functional Constipation: A Nonrandomized, Open-Label Trial

OBJECTIVES

Pediatric functional constipation (PFC) affects up to 30% of children. Current treatments often do not sustain symptomatic relief. Lubiprostone is a locally acting chloride channel activator that promotes fluid secretion into the small bowel without affecting serum electrolyte concentrations. We assessed the safety/tolerability of oral lubiprostone as treatment for PFC in a 24-week study.

METHODS

This phase 3 open-label safety trial conducted from April-November 2016 at 13 US sites included patients (ages 6-17 years) diagnosed with PFC (Rome III criteria). Patients <50 and ≥50 kg received lubiprostone 12 or 24 mcg twice daily, respectively, for 24 weeks. Safety endpoints included incidence of treatment-emergent adverse events (TEAEs) and changes from baseline in clinical laboratory parameters and vital signs.

RESULTS

Overall, 87 patients receiving lubiprostone, 64.3% (36/56) in the 12-mcg group and 54.8% (17/31) in the 24-mcg group, completed the study. Of 12 TEAEs leading to discontinuation, only upper abdominal pain occurred in >1 patient. TEAEs were mostly mild in intensity, with gastrointestinal disorders (diarrhea, vomiting) most frequently reported. No safety concerns were found in vital signs, abbreviated physical examinations, and laboratory tests. Subgroup analyses assessed an impact of age, sex, and race categories on TEAEs and treatment-related adverse events. Mean investigators' assessments of treatment effectiveness (scale of 0-4) for lubiprostone 12- and 24-mcg groups, respectively, were 2.8 and 2.9 at week 12, and 2.7 and 2.2 at week 24.

CONCLUSIONS

Lubiprostone was well tolerated in the pediatric population. The incidence of TEAEs was comparable to that observed in previous clinical trials and in adults.

Safety of elobixibat and lubiprostone in Japanese patients with chronic constipation: a retrospective cohort study

BACKGROUND

We aimed to discuss and compare reported adverse reactions and drug add-ons associated with elobixibat and lubiprostone use in chronic constipation treatment, as the safety of these drugs has not been well examined in post-marketing clinical settings.

RESEARCH DESIGN AND METHODS

In this retrospective cohort study, using records of community pharmacies in Japan, we identified new users of elobixibat and lubiprostone. The Japan Pharmaceutical Association sent questionnaires regarding baseline and event data to community pharmacists. The incidence of events and hazard ratio (HR) associated with the study drugs were evaluated.

RESULTS

New users of elobixibat (n = 979) and lubiprostone (n = 829) were identified (mean age: 74 and 77 years; females: 59% and 53%, respectively). Although the crude risk ratio of adverse events for elobixibat was 0.79 (95% confidence interval: 0.63-0.99), there was no significant difference in the HR for any of the common events, including drug add-ons (n ≥ 5), compared with those for lubiprostone.

CONCLUSION

No new safety concerns have been raised in relation to elobixibat and lubiprostone use for treating chronic constipation, although the HR of different events varied. Further larger-scale study is needed as the estimates for events of small numbers were unstable.

Effects of Lubiprostone, an Intestinal Secretagogue, on Electrolyte Homeostasis in Chronic Idiopathic and Opioid-induced Constipation

GOALS

To assess short-term and long-term effects of lubiprostone, a type-2 chloride channel activator, on electrolyte homeostasis.

BACKGROUND

Conventional laxatives are associated with electrolyte imbalances. Lubiprostone is a type-2 chloride channel activator approved for treating chronic idiopathic constipation (CIC), opioid-induced constipation (OIC), and constipation-predominant irritable bowel syndrome in women. It induces intestinal fluid secretion, possibly affecting water and electrolyte homeostasis. We investigated short-term and long-term effects of lubiprostone on electrolyte, blood urea nitrogen (BUN), and creatinine levels using pooled data from CIC and OIC patients.

STUDY

Data were pooled from 10 CIC and OIC studies-6 double-blind, randomized, placebo-controlled studies and 4 open-label, long-term studies. Total duration of lubiprostone exposure was from 3 weeks (short-term: CIC, 3 to 4 wk; OIC, placebo-controlled, 12 wk) to 48 weeks (long-term: CIC, 24 to 48 wk; OIC, 48 wk). Sodium, chloride, potassium, magnesium, BUN, and creatinine levels were examined at baseline and final assessment.

RESULTS

Overall, 3209 patients were assessed. In the double-blind, placebo-controlled studies, there were no clinically meaningful differences in levels of electrolytes, BUN, and creatinine between lubiprostone and placebo groups, and in changes from baseline levels with long-term use of lubiprostone. Analyses of shifts in laboratory values (low/normal/high) at baseline and final assessment showed minimal effects on electrolytes, BUN, and creatinine.

CONCLUSIONS

Lubiprostone did not cause clinically meaningful electrolyte imbalances or affect markers of renal function in either the short-term or long-term treatment of CIC or OIC.

Opioid-Induced Constipation in Advanced Cancer Patients

The present study discusses opioid-induced constipation (OIC) in advanced cancer patients, focusing on the OIC definition, pathophysiology, and treatment. OIC is any change from baseline defecation patterns and bowel habits that developed after starting opioid therapy. The condition is characterized by bowel frequency reduction, worsening or development of straining, a sensation of incomplete defecation, or distress associated with bowel habits. OIC is common in advanced cancer patients, with a prevalence of approximately 51%-87% in patients taking opioids for pain management. Patients are likely to experience severe distress, work productivity reduction, poor quality of life, and increased healthcare utilization. OIC has a complex pathophysiology that involves propulsive and peristalsis impairment, intestinal mucosal secretion inhibition, intestinal fluid absorption enhancement, and anal sphincters function impairment. The Rome III criteria are used to assess and diagnose clinical OIC and can also be diagnosed through the Patient Assessment of Constipation (PAC) measures, including the symptom survey (PAC-SYM) and quality of life survey (PAC-QOL). Non-pharmacological treatment of OIC involves lifestyle habits and dietary adjustments, although these interventions might be insufficient to manage the condition. Pharmacological treatments involve the use of traditional laxatives and newer agents like peripherally acting mu-opioid receptor agonists (PAMORAs), including naldemedine, naloxegol, and methylnaltrexone. More novel treatments for OIC that target the pathophysiology are still needed and should be studied carefully for safety and efficacy.

Prostaglandin E2 receptors and their role in gastrointestinal motility - Potential therapeutic targets

Prostaglandin E2 (PGE2) is found throughout the gastrointestinal tract in a diverse variety of functions and roles. The recent discovery of four PGE2 receptor subtypes in intestinal muscle layers as well as in the enteric plexus has led to much interest in the study of their roles in gut motility. Gut dysmotility has been implicated in functional disease processes including irritable bowel syndrome (IBS) and slow transit constipation, and lubiprostone, a PGE2 derivative, has recently been licensed to treat both conditions. The diversity of actions of PGE2 in the intestinal tract is attributed to its differing effects on its downstream receptor types, as well as their varied distribution in the gut, in both health and disease. This review aims to identify the role and distribution of PGE2 receptors in the intestinal tract, and aims to elucidate their distinct role in gut motor function, with a specific focus on functional intestinal pathologies.

Importance of Non-pharmacological Approaches for Treating Irritable Bowel Syndrome: Mechanisms and Clinical Relevance

Chronic visceral pain represents a major unmet clinical need with the severity of pain ranging from mild to so severe as to prevent individuals from participating in day-to-day activities and detrimentally affecting their quality of life. Although chronic visceral pain can be multifactorial with many different biological and psychological systems contributing to the onset and severity of symptoms, one of the major triggers for visceral pain is the exposure to emotional and physical stress. Chronic visceral pain that is worsened by stress is a hallmark feature of functional gastrointestinal disorders such as irritable bowel syndrome (IBS). Current pharmacological interventions for patients with chronic visceral pain generally lack efficacy and many are fraught with unwanted side effects. Cognitive behavioral therapy (CBT) has emerged as a psychotherapy that shows efficacy at ameliorating stress-induced chronic visceral pain; however, the molecular mechanisms underlying CBT remain incompletely understood. Preclinical studies in experimental models of stress-induced visceral pain employing environmental enrichment (EE) as an animal model surrogate for CBT are unraveling the mechanism by which environmental signals can lead to long-lasting changes in gene expression and behavior. Evidence suggests that EE signaling interacts with stress and nociceptive signaling. This review will (1) critically evaluate the behavioral and molecular changes that lead to chronic pain in IBS, (2) summarize the pharmacological and non-pharmacological approaches used to treat IBS patients, and (3) provide experimental evidence supporting the potential mechanisms by which CBT ameliorates stress-induced visceral pain.

A meta-analysis of randomized controlled trials of the addition of lubiprostone to bowel preparation before colonoscopy

AIM

Adequate bowel preparation is essential to the quality of colonoscopy. We performed a meta-analysis to determine the efficacy and safety of the addition of lubiprostone to the bowel preparation process prior to colonoscopy.

METHODS

Online databases, namely, PubMed, MEDLINE and Cochrane Library, were searched for randomized controlled trials that assessed the additive effect of lubiprostone on the quality of colon preparation in patients undergoing colonoscopy. Each included study was evaluated by the Jadad score to assess the quality of the study. The primary outcome was bowel preparation efficacy, defined as the proportion of patients with an excellent or poor preparation. The secondary outcomes included the length of the colonoscopy, polyp detection, and any adverse effects.

RESULTS

In total, 5 articles published between 2008 and 2016 fulfilled the selection criteria. The addition of lubiprostone to the bowel cleansing process significantly increased the proportion of patients with an excellent preparation (risk ratio [RR] = 1.68, 95% confidence interval (CI): 1.40-2.02, P < .00001) but did not decrease the procedural time or increase the polyp detection rate (mean difference = -0.52, 95% CI: -3.74-2.69, P = .75; RR = 1.16, 95% CI: 0.96-1.42, P = .13, respectively). There was no significant difference in the proportion of patients with any adverse events.

CONCLUSION

The addition of lubiprostone to the bowel preparation regimen prior to colonoscopy is effective and safe.

Recent advances in the pharmacological management of constipation predominant irritable bowel syndrome

Introduction: Irritable bowel syndrome (IBS) is a complex functional gut disorder that typically manifests in early adult years. More than a third of IBS patients are diagnosed with predominant constipation subtype (IBS-C). This syndrome has a distressing impact on the quality of life and is challenging both for patients and physicians.Areas covered: This review focuses on the pathophysiology of constipation in IBS and presents current management options. It also covers the latest findings that may lead to novel pharmacological options in IBS-C management. The authors intend to highlight the results of published research including abstracts, records from the clinicaltrials.gov database (second and third phases of the study) and information from original FDA documents.Expert opinion: Current therapeutic options for IBS-C treatment are based on linaclotide, lubiprostone, plecanatide, and the reintroduced tegaserod. Drugs present on the market as well as those in pre-clinical development should increase the lower esophageal sphincter pressure, promote gastric motility, accelerate gastric emptying and improve gastro-duodenal coordination. Most significantly, they shall not induce severe side effects.

Clozapine: why wait to start a laxative?

Clozapine, the antipsychotic of choice for treatment-resistant schizophrenia, has a number of side-effects, some of which are potentially life-threatening. Historically viewed as a relatively minor side-effect, there is increasing awareness of the potentially severe sequalae of constipation secondary to clozapine-induced gastrointestinal hypomotility (CIGH). These include ileus, intestinal obstruction, bowel ischaemia, gastrointestinal necrosis, toxic megacolon and death. CIGH is significantly more common than clozapine-induced blood dyscrasias and has a higher mortality rate. Although strict criteria must be followed to assertively monitor, detect and treat blood dyscrasias in patients taking clozapine, no such framework exists for CIGH. We recommend that prescribing guidelines, regulatory agencies and information from manufacturers should more clearly highlight the risks identified in the literature. Furthermore, we recommend that, in people taking clozapine, constipation should be prevented by prophylactic treatment with laxatives rather than treated only when clinically identified.

LEARNING OBJECTIVES:

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Effectiveness and tolerability of linaclotide in the treatment of IBS-C in a "real-life" setting: Results from a Portuguese single-center study

BACKGROUND

Although linaclotide has been approved to treat moderate to severe IBS-C, no data are available on its effectiveness and tolerability in patients in a real-life setting.

METHODS

A prospective single-center study of the effectiveness and tolerability of linaclotide was carried out on patients (n = 40) with moderate to severe IBS-C, all fulfilling the Rome IV criteria. Clinical information was recorded using a dietary questionnaire at baseline, and 3 and 6 months after initiating treatment. The end-points to measure effectiveness included abdominal pain and bloating (11-NRS), the number of bowel movements and patient satisfaction. Tolerability was assessed through the frequency of adverse events.

KEY RESULTS

In terms of efficacy, an improvement in abdominal pain and in the intensity of bloating was evident in the cohort after 6 months of linaclotide therapy. The proportion of patients with moderate or severe symptoms of bloating fell from 93.3% to 33.3% and those with pain from 93.4% to 20%. Weekly bowel movements also improved and accordingly, 97% of the patients were moderately or very satisfied with the treatment. At the end of the study, diarrhea was the most frequent adverse event (10%), although it was considered mild in 66.7% of these subjects and moderate in 33.3%. A lack of efficacy (n = 3) and excessive diarrhea (n = 7) were motives for discontinuing the treatment.

CONCLUSIONS AND INFERENCES

Linaclotide proved to be a safe and effective drug to reduce the main symptoms of IBS-C in everyday clinical practice, with an improvement comparable to that seen in clinical trials.

Copper-mediated cascade radical cyclization of olefins with naphthalenyl iododifluoromethyl ketones

Copper-mediated radical cyclization of naphthalenyl iododifluoromethyl ketones with olefins was developed to generate a series of unprecedented gem-difluorodihydrophenanthrenones with excellent regioselectivity.

Clinical utility of plecanatide in the treatment of chronic idiopathic constipation

Constipation is an important health burden that reduces the quality of life for countless millions of people. Symptom-centric therapeutics are often used to treat constipation due to unknown etiology, but in many cases, these drugs are either inadequate or have significant side effects. More recently, synthetic peptide agonists for epithelial guanylyl cyclase C (GC-C) have been developed which are effective at treating constipation in a sub-population of adult constipation patients. The first to market was linaclotide that is structurally related to the diarrheagenic enterotoxin, but this was followed by plecanatide, which more closely resembles endogenous uroguanylin. Both the drugs exhibit almost identical clinical efficacy in about 20% of patients, with diarrhea being a common side effect. Despite the potential for reduced side effects with plecanatide, detailed analysis suggests that clinically, they are very similar. Ongoing clinical and preclinical studies with these drugs suggest that treating constipation might be the tip of the iceberg in terms of clinical utility. The expression of cGMP signaling components could be diagnostic for functional bowel disorders, and increasing cGMP using GC-C agonists or phosphodiesterase inhibitors has huge potential for treating enteric pain, ulcerative colitis, and for the chemoprevention of colorectal cancer.

Progress in understanding mechanisms of opioid-induced gastrointestinal adverse effects and respiratory depression

Opioids evoke analgesia through activation of opioid receptors (predominantly the μ opioid receptor) in the central nervous system. Opioid receptors are abundant in multiple regions of the central nervous system and the peripheral nervous system including enteric neurons. Opioid-related adverse effects such as constipation, nausea, and vomiting pose challenges for compliance and continuation of the therapy for chronic pain management. In the post-operative setting opioid-induced depression of respiration can be fatal. These critical limitations warrant a better understanding of their underpinning cellular and molecular mechanisms to inform the design of novel opioid analgesic molecules that are devoid of these unwanted side-effects. Research efforts on opioid receptor signalling in the past decade suggest that differential signalling pathways and downstream molecules preferentially mediate distinct pharmacological effects. Additionally, interaction among opioid receptors and, between opioid receptor and non-opioid receptors to form signalling complexes shows that opioid-induced receptor signalling is potentially more complicated than previously thought. This complexity provides an opportunity to identify and probe relationships between selective signalling pathway specificity and in vivo production of opioid-related adverse effects. In this review, we focus on current knowledge of the mechanisms thought to transduce opioid-induced gastrointestinal adverse effects (constipation, nausea, vomiting) and respiratory depression.

Targeting Small Bowel Receptors to Treat Constipation and Diarrhea

BACKGROUND

The options for the treatment of diarrhea and constipation are evolving as emerging therapies target small bowel receptors. The goal of this review is to discuss small bowel receptors involved in intestinal absorption, secretion, and motility. The review highlights therapies already approved or currently being studied for the modulation of these receptors.

METHODS

The articles cited in this review focus on the molecular level of pathways involved in diarrhea and constipation, and highlight the respective pharmacotherapies.

RESULTS

The majority of the studies in the current literature investigate the effects of both the small and large intestine receptors on diarrhea and constipation. There are fewer studies that isolate the effects of these receptors solely on the small bowel, and focusing more on the receptors found distinctly in the small intestine may be an area of interest for future studies as this can inspire more targeted therapies.

Luminally Acting Agents for Constipation Treatment: A Review Based on Literatures and Patents

Constipation is one of the most frequently reported gastrointestinal (GI) disorders that negatively impacts quality of life and is associated with a significant economic burden to the patients and society. Traditional treatments including lifestyle modification and laxatives are often ineffective in the more severe forms of constipation and over the long term. New medications targeting at intestinal chloride channels and colonic serotonin receptors have been demonstrated effective in recent years. Emerging agents focusing on improving intestinal secretion and/or colonic motility have been shown effective in animal models and even in clinical trials. Recognization of the role of cystic fibrosis transmembrane regulator (CFTR) and calcium-activated chloride channels (CaCCs) in intestine fluid secretion and motility modulation makes CFTR and CaCCs promising molecule targets for anti-constipation therapy. Although there are multiple choices for constipation treatment, there is still a recognized need for new medications in anti-constipation therapy. The present review covers the discovery of luminally acting agents for constipation treatment described in both patents (2011–present) and scientific literatures.

Clinical Practice Guideline: Irritable bowel syndrome with constipation and functional constipation in the adult

In this Clinical Practice Guideline we discuss the diagnostic and therapeutic approach of adult patients with constipation and abdominal complaints at the confluence of the irritable bowel syndrome spectrum and functional constipation. Both conditions are included among the functional bowel disorders, and have a significant personal, healthcare, and social impact, affecting the quality of life of the patients who suffer from them. The first one is the irritable bowel syndrome subtype, where constipation represents the predominant complaint, in association with recurrent abdominal pain, bloating, and abdominal distension. Constipation is characterized by difficulties with or low frequency of bowel movements, often accompanied by straining during defecation or a feeling of incomplete evacuation. Most cases have no underlying medical cause, and are therefore considered as a functional bowel disorder. There are many clinical and pathophysiological similarities between both disorders, and both respond similarly to commonly used drugs, their primary difference being the presence or absence of pain, albeit not in an "all or nothing" manner. Severity depends not only upon bowel symptom intensity but also upon other biopsychosocial factors (association of gastrointestinal and extraintestinal symptoms, grade of involvement, and perception and behavior variants). Functional bowel disorders are diagnosed using the Rome criteria. This Clinical Practice Guideline has been made consistent with the Rome IV criteria, which were published late in May 2016, and discuss alarm criteria, diagnostic tests, and referral criteria between Primary Care and gastroenterology settings. Furthermore, all the available treatment options (exercise, fluid ingestion, diet with soluble fiber-rich foods, fiber supplementation, other dietary components, osmotic or stimulating laxatives, probiotics, antibiotics, spasmolytics, peppermint essence, prucalopride, linaclotide, lubiprostone, biofeedback, antidepressants, psychological therapy, acupuncture, enemas, sacral root neurostimulation, surgery) are discussed, and practical recommendations are made regarding each of them.

[Irritable bowel syndrome with constipation and functional constipation in adults: Treatment (Part 2 of 2)]

In this Clinical practice guide we examine the diagnostic and therapeutic management of adult patients with constipation and abdominal discomfort, at the confluence of the spectrum of irritable bowel syndrome and functional constipation. Both fall within the framework of functional intestinal disorders and have major personal, health and social impact, altering the quality of life of the patients affected. The former is a subtype of irritable bowel syndrome in which constipation and altered bowel habit predominate, often along with recurring abdominal pain, bloating and abdominal distension. Constipation is characterised by infrequent or hard-to-pass bowel movements, often accompanied by straining during defecation or the sensation of incomplete evacuation. There is no underlying organic cause in the majority of cases; it being considered a functional bowel disorder. There are many clinical and pathophysiological similarities between the two conditions, the constipation responds in a similar way to commonly used drugs, the fundamental difference being the presence or absence of pain, but not in an "all or nothing" way. The severity of these disorders depends not only on the intensity of the intestinal symptoms but also on other biopsychosocial factors: association of gastrointestinal and extraintestinal symptoms, degree of involvement, forms of perception and behaviour. Functional bowel disorders are diagnosed using the Rome criteria. This Clinical practice guide adapts to the Rome IV criteria published at the end of May 2016. The first part (96, 97, 98) examined the conceptual and pathophysiological aspects, alarm criteria, diagnostic test and referral criteria between Primary Care and Gastroenterology. This second part reviews all the available treatment alternatives (exercise, fluid ingestion, diet with soluble fibre-rich foods, fibre supplements, other dietary components, osmotic or stimulating laxatives, probiotics, antibiotics, spasmolytics, peppermint essence, prucalopride, linaclotide, lubiprostone, biofeedback, antdepressants, psychological treatment, acupuncture, enemas, sacral root neurostimulation and surgery), and practical recommendations are made for each.

Functional Disorders: Slow-Transit Constipation

Constipation is a very common complaint, with slow-transit constipation (STC) accounting for a significant proportion of cases. Old age, female gender, psychiatric illness, and history of sexual abuse are all associated with STC. The exact cause of STC remains elusive; however, multiple immune and cellular changes have been demonstrated. Diagnosis requires evidence of slowed colonic transit which may be achieved via numerous modalities. While a variety of medical therapies exist, these are often met with limited success and a minority of patients ultimately require operative intervention. When evaluating a patient with STC, it is important to determine the presence of concomitant obstructed defecation or other forms of enteric dysmotility, as this may affect treatment decisions. Although a variety of surgical procedures have been reported, subtotal colectomy with ileorectal anastomosis is the most commonly performed and well-studied procedure, with the best track record of success.

Chronic Constipation: a Review of Current Literature

Chronic constipation is a common health condition representing a substantial proportion of primary care visits and referrals to specialist providers. Chronic constipation can have a significant negative effect on health-related quality of life and has been associated with psychological distress in severely affected patients. It has the potential to cause patients to curtail work, school, and social activities. While different pathophysiological mechanisms have been implicated in the development of chronic constipation, in some instances, the causes of chronic constipation are not easily determined. Expenditures for the evaluation and management of chronic constipation represent a significant burden on patients and payers, and it is important for clinicians to have a clear understanding of the different pathophysiological mechanisms associated with constipation, understand the different testing modalities and treatments that are available including their appropriateness and limitations, and tailor that knowledge to the management of individual patients.

Beyond pancreatic insufficiency and liver disease in cystic fibrosis

Cystic fibrosis is a life shortening hereditary disease, primarily leading to progressive pulmonary infection and exocrine pancreatic dysfunction. Several gastrointestinal complications other than malabsorption can arise during the disease course and with the progressively increasing life span of patients with CF; new and more rare complications are being recognized. We review the literature on gastrointestinal manifestations in CF, excluding the liver and pancreas.

CONCLUSION

We describe the clinical presentation and treatment of more common conditions like gastroesophageal reflux, small intestinal bacterial overgrowth, intussusception, meconium ileus, distal intestinal obstruction syndrome, and constipation, and we also discuss what is known on celiac disease, appendicitis, fibrosing colonopathy, inflammation and inflammatory bowel disease and gastrointestinal cancer.

WHAT IS KNOWN

• Gastrointestinal complications arise early in the course of the disease and have a severe impact on the quality of life of the patients. What is New: • This review is a concise summary of the current literature on gastrointestinal complications of cystic fibrosis. • We focused on clinical presentation and diagnostic investigations and provide a comprehensive resume of the current treatment options.

Gastrointestinal Diseases in Pregnancy: Nausea, Vomiting, Hyperemesis Gravidarum, Gastroesophageal Reflux Disease, Constipation, and Diarrhea

Many disorders of the gastrointestinal tract are common in pregnancy. Elevated levels of progesterone may lead to alterations in gastrointestinal motility which could contribute to nausea, vomiting, and/or GERD. Pregnancy-induced diarrhea may be due to elevated levels prostaglandins. This article reviews the normal physiologic and structural changes associated with pregnancy that could contribute to many of the common gastrointestinal complaints in pregnant patients. Additionally, the appropriate clinical and laboratory evaluations, other pathologic conditions that should be included in the differential, as well as the nonpharmacologic and pharmacologic therapies for each of these conditions is discussed.

Rare medical manifestations of severe restricting and purging: "Zebras," missed diagnoses, and best practices

OBJECTIVE

Medical problems that arise due to severe restricting and/or purging may be misdiagnosed or suboptimally treated, from outpatient clinics to top medical hospitals. A symptom may be presumed to be a psychological manifestation of the eating disorder and inappropriately dismissed for further medical evaluation. Alternatively, a detailed medical workup may be performed, overlooking a classic relationship between starvation and a physical finding, which delays referral to eating disorder care. This review article focuses on rare medical issues (also called "zebras" in medical training), diagnoses that may be missed in patients with eating disorders, and best practices for management, organized by organ system.

METHOD

A PubMed search was performed, using search terms "eating disorder," "anorexia nervosa," and "bulimia nervosa" in combination with different words for each organ system and known medical manifestations of severe eating disorders, with high quality and relevant studies from the past 20 years cited.

DISCUSSION

Adults with eating disorders may present with extreme organ dysfunction and atypical signs and symptoms of typical medical problems. Timely diagnosis, risk awareness, appropriate treatment, and avoidance of harm are all vital. With judicious management and nutritional rehabilitation, most of these complications will significantly improve or resolve. ©

The Pharmacology of Visceral Pain

Visceral pain describes pain emanating from the internal thoracic, pelvic, or abdominal organs. Unlike somatic pain, visceral pain is generally vague, poorly localized, and characterized by hypersensitivity to a stimulus such as organ distension. While current therapeutics provides some relief from somatic pain, drugs used for treatment of chronic visceral pain are typically less efficacious and limited by multiple adverse side effects. Thus, the treatment of visceral pain represents a major unmet medical need. Further, more basic research into the physiology and pathophysiology of visceral pain is needed to provide novel targets for future drug development. In concert with chronic visceral pain, there is a high comorbidity with stress-related psychiatric disorders including anxiety and depression. The mechanisms linking visceral pain with these overlapping comorbidities remain to be elucidated. However, persistent stress facilitates pain perception and sensitizes pain pathways, leading to a feed-forward cycle promoting chronic visceral pain disorders. We will focus on stress-induced exacerbation of chronic visceral pain and provide supporting evidence that centrally acting drugs targeting the pain and stress-responsive brain regions may represent a valid target for the development of novel and effective therapeutics.