Safety assessment of prucalopride in elderly patients with constipation: a double-blind, placebo-controlled study

Prucalopride and Bowel Function Post Gastrointestinal Surgery: Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Prolonged postoperative ileus (PPOI) contributes to morbidity and prolonged hospitalization. Prucalopride, a selective 5-hydroxytryptamine receptor agonist, may enhance bowel motility. This review assesses whether the perioperative use of prucalopride compared to placebo is associated with accelerated return of bowel function post gastrointestinal (GI) surgery.

METHODS

OVID, CENTRAL, and EMBASE were searched as of January 2024 to identify randomized controlled trials (RCTs) comparing prucalopride and placebo for prevention of PPOI in adult patients undergoing GI surgery. The primary outcomes were time to stool, time to flatus, and time to oral tolerance. The secondary outcomes were incidence of PPOI, length of stay (LOS), postoperative complications, adverse events, and overall costs. The Cochrane risk of bias tool for randomized trials and the Grading of Recommendations, Assessment, Development, and Evaluations framework were used. An inverse variance random effects model was used.

RESULTS

From 174 citations, 3 RCTs with 139 patients in each treatment group were included. Patients underwent a variety of GI surgeries. Patients treated with prucalopride had a decreased time to stool (mean difference 36.82 hours, 95% CI 59.4 to 14.24 hours lower, I2 = 62%, low certainty evidence). Other outcomes were not statistically significantly different (very low certainty evidence). Postoperative complications and adverse events could not be meta-analyzed due to heterogeneity; yet individual studies suggested no significant differences (very low certainty evidence).

DISCUSSION

Current RCT evidence suggests that prucalopride may enhance postoperative return of bowel function. Larger RCTs assessing patient important outcomes and associated costs are needed before routine use of this agent.

Prokinetics-safety and efficacy: The European Society of Neurogastroenterology and Motility/The American Neurogastroenterology and Motility Society expert review

BACKGROUND

Prokinetics are a class of pharmacological drugs designed to improve gastrointestinal (GI) motility, either regionally or across the whole gut. Each drug has its merits and drawbacks, and based on current evidence as high-quality studies are limited, we have no clear recommendation on one class or other. However, there remains a large unmet need for both regionally selective and/or globally acting prokinetic drugs that work primarily intraluminally and are safe and without systemic side effects.

PURPOSE

Here, we describe the strengths and weaknesses of six classes of prokinetic drugs, including their pharmacokinetic properties, efficacy, safety and tolerability and potential indications.

Constipation in Patients With Chronic Kidney Disease

Constipation is a frequent symptom in patients with chronic kidney disease (CKD). This review outlines the mechanisms and management of constipation in patients with CKD from a physician's perspective. Common causes of constipation in patients with CKD include concomitant medications, low dietary fiber intake, water-restricted diet, lack of physical activity, altered gut microbiota, and reduced gastrointestinal motility. Constipation has a negative impact on overall health, and, in particular, the presence of constipation has been associated with worsening kidney function and increased risk of developing advanced stages of CKD. Although lifestyle and dietary modifications may not always be practical for patients with CKD, they are recommended because they are beneficial as they lower mortality in patients with CKD. The use of laxatives containing magnesium salts, bulking agents, and osmotic laxatives may have insufficient efficacy and may be associated with adverse effects. In contrast, lactulose and lubiprostone have been shown to exhibit reno-protective effects. Linaclotide and plecanatide have very limited systemic absorption and appear safe in patients with CKD. Tenapanor reduces paracellular intestinal phosphate absorption in addition to blocking sodium uptake by enterocytes, and provides additional benefit in patients patients with CKD who have hyperphosphatemia and constipation. Prucalopride leads to improvements in bowel function and constipation-related symptoms in cases in which response to conventional laxatives are inadequate. However, the dose of prucalopride should be reduced to 1 mg once daily for patients with CKD. In conclusion, there are important advances on the impact and treatment of constipation in patients with CKD.

Pharmacological and nutritional therapy of children and adults with chronic intestinal pseudo-obstruction

INTRODUCTION

Chronic intestinal pseudo-obstruction (CIPO) is a rare, heterogeneous and severe form of gastrointestinal dysmotility.

AREAS COVERED

Pertinent literature on pediatric and adult CIPO management has been assessed via PubMed, Scopus, and EMBASE from inception to June 2022. Prokinetics, aimed at restoring intestinal propulsion (e.g. orthopramides and substituted benzamides, acetyl cholinesterase inhibitors, serotonergic agents and others), have been poorly tested and the available data showed only partial efficacy. Moreover, some prokinetic agents (e.g. orthopramides and substituted benzamides) can cause major side effects. The CIPO-related small intestinal bacterial overgrowth requires treatment preferably via poorly absorbable antibiotics to avoid bacterial resistance. Apart from opioids, which worsen gut motility, analgesics should be considered to manage visceral pain, which might dominate the clinical manifestations. Nutritional support, via modified oral feeding, enteral or parenteral nutrition, is key to halt CIPO-related malnutrition.

EXPERT OPINION

There have been significant roadblocks preventing the development of CIPO treatment. Nonetheless, the considerable advancement in neurogastroenterology and pharmacological agents cast hopes to test the actual efficacy of new prokinetics via well-designed clinical trials. Adequate dietary strategies and supplementation remain of crucial importance. Taken together, novel pharmacological and nutritional options are expected to provide adequate treatments for these patients.

Tissue distribution and abuse potential of prucalopride: findings from non-clinical and clinical studies

Background

Prucalopride is a selective serotonin type 4 (5-HT₄) receptor agonist indicated for treatment of chronic idiopathic constipation (CIC) in adults (2 mg orally, daily). 5-HT₄ receptors are present in the central nervous system; therefore, non-clinical and clinical assessments were performed to evaluate the tissue distribution and abuse potential of prucalopride.

Methods

In vitro receptor-ligand binding studies were performed to assess the affinity of prucalopride (≤1 mM) for peptide receptors, ion channels, monoamine neurotransmitters and 5-HT receptors. The tissue distribution of ¹⁴C-prucalopride (5 mg base-equivalent/kg) was investigated in rats. Behavioural assessments in mice, rats and dogs after treatment with single or repeated (up to 24 months) subcutaneous or oral doses of prucalopride (0.02-640 mg/kg across species) were performed. Treatment-emergent adverse events possibly indicative of abuse potential during prucalopride CIC clinical trials were evaluated.

Results

Prucalopride showed no appreciable affinity for the receptors and ion channels investigated; its affinity (at ≤100 μM) for other 5-HT receptors was 150-10,000 times lower than that for the 5-HT₄ receptor. In rats, <0.1% of the administered dose was found in the brain and concentrations were below the limit of detection within 24 hours. At supratherapeutic doses (≥20 mg/kg), mice and rats exhibited palpebral ptosis, and dogs exhibited salivation, eyelid tremors, decubitis, pedalling movements and sedation. All clinical treatment-emergent adverse events, possibly indicative of abuse potential, except dizziness, occurred in <1% of patients treated with prucalopride or placebo.

Conclusion

This series of non-clinical and clinical studies suggest low abuse potential for prucalopride.

Medical Management of Constipation in Elderly Patients: Systematic Review

Background/Aims

Constipation is a common gastrointestinal problem in the elderly. Because of the limitations of life style modifications and the comorbidity, laxative use is also very common. Therefore, this study reviews the latest literature on the effect and safety of laxative in the elderly.

Methods

A systematic review of randomized controlled trials investigating the effectiveness and safety of laxatives for constipation in elderly patients over 65 years old were performed using the following databases PubMed, EMBASE, and the Cochrane Library.

Results

Twenty-three randomized controlled trials were included in this review. Among the selected studies, 9 studies compared laxative with placebo and 5 studies compared laxatives of the same type. Four studies compared different types of laxatives or compared combination agents. Five studies compared novel medications such as prucalopride, lubiprostone, and elobixibat with placebo. Psyllium, calcium polycarbophil, lactulose syrup, lactitol, polyethylene glycol, magnesium hydroxide, stimulant laxative with or without fiber, and other medications were more effective than placebo in elderly constipation patients in short-term. Generally, the frequency and severity of adverse effects of laxative were similar between the arms of studies.

Conclusions

Bulk laxative, osmotic laxative, stimulant laxative with or without fiber, and other medications can be used in elderly patients in short-term within 3 months with reasonable safety. However, the quality of included studies was not high and most of studies was conducted in a small number of patients. Among these laxatives, polyethylene glycol seems to be safe and effective in long-term use of about 6 months in elderly patients.

Current Opinion on Prucalopride in Gastroparesis and Chronic Constipation Treatment: A Focus on Patient Selection and Safety

Prucalopride is a third-generation, highly selective 5-hydroxytryptamine 4 (5-HT4) receptor agonist. Many recent studies indicate prucalopride may play an important role in various motility disorders. The aim of this study was to investigate safety and patient selection considerations when using prucalopride as gastroparesis and chronic constipation treatment. We systematically searched PubMed, Embase, the Cochrane Central Register and ClinicalTrials.gov, and we reviewed all studies that evaluated prucalopride for the treatment of gastroparesis and chronic idiopathic constipation in adults. Prucalopride is an effective and safe option based on all the studies currently conducted. Thus, it may be the first-line treatment in the future. Prucalopride has the potential to be useful in the treatment of functional constipation and other forms of gastrointestinal diseases (eg, gastroparesis). Through the research on this potential, prucalopride is expected to be a useful and versatile option for treating gastrointestinal diseases in the future.

Different doses of prucalopride in treating chronic idiopathic constipation: a meta-analysis and Bayesian analysis

OBJECTIVE

This study aims to explore the incremental benefit of different doses of prucalopride in treating chronic idiopathic constipation (CIC).

METHODS

PubMed, EMBASE, MEDLINE, Cochrane Library, Chinese Biomedical Database, China National Knowledge Infrastructure, VIP medicine information and Wanfang databases were comprehensively searched up to March 2020. Prospective trials with different doses of prucalopride versus placebo were selected. The frequency of spontaneous bowel movements (SBMs) per week and the treatment-emergent adverse events (TEAEs), such as headache, arrhythmia, diarrhoea, dizziness, nausea and vomiting, were first synthesised in a meta-analysis. The probability of optimal dose of prucalopride was then ranked by random-effects within Bayesian analysis.

RESULTS

14 high-quality randomised controlled trials with 4328 patients were ultimately included. SBMs per week increased significantly after using 1 mg (OR: 2.40, 95% CI 1.32 to 4.37), 2 mg (OR: 2.55, 95% CI 1.93 to 3.36) and 4 mg (OR: 2.51, 95% CI 1.92 to 3.28) prucalopride. Bayesian analysis demonstrated 1 mg dose obtained the maximum SBMs per week (OR: 3.31, 95% credible interval 1.72 to 6.16, probability rank=0.70) indirectly compared with 2 mg and 4 mg doses. TEAEs were higher significantly in 2 mg (risk ratio (RR): 1.20, 95% CI 1.09 to 1.33) and 4 mg (RR: 1.14, 95% CI 1.07 to 1.22) prucalopride. The 1 mg dose did not reach statistical significance (RR: 1.17, 95% CI 0.94 to 1.44).

CONCLUSIONS

The study concludes that 1 mg dose at commencement could be safer in treating CIC and that 2 mg prucalopride could be more efficacious in terms of SBMs per week outcome receiving.

PROSPERO REGISTRATION NUMBER

CRD42019136679.

Constipation and Fecal Incontinence in the Elderly

PURPOSE OF REVIEW

To review the epidemiology, pathogenesis, clinical features, and management of primary constipation and fecal incontinence in the elderly.

RECENT FINDINGS

Among elderly people, 6.5%, 1.7%, and 1.1% have functional constipation, constipation-predominant IBS, and opioid-induced constipation. In elderly people, the number of colonic enteric neurons and smooth muscle functions is preserved; decreased cholinergic function with unopposed nitrergic relaxation may explain colonic motor dysfunction. Less physical activity or dietary fiber intake and postmenopausal hormonal therapy are risk factors for fecal incontinence in elderly people. Two thirds of patients with fecal incontinence respond to biofeedback therapy. Used in combination, loperamide and biofeedback therapy are more effective than placebo, education, and biofeedback therapy. Vaginal or anal insert devices are another option. In the elderly, constipation and fecal incontinence are common and often distressing symptoms that can often be managed by addressing bowel disturbances. Selected diagnostic tests, prescription medications, and, infrequently, surgical options should be considered when necessary.

Efficacy and Tolerability of Prucalopride in Bowel Preparation for Colonoscopy: A Systematic Review and Meta-Analysis

INTRODUCTION

Adequate bowel preparation is a vital determinant for the success of colonoscopy. However, individuals who undergo bowel preparation for colonoscopy can experience major discomfort. To solve this problem, adding prucalopride to the prepared solution may reduce intake volume, decreasing discomfort and side effects. We performed meta-analyses and systematic review of available randomized controlled trials.

METHODS

Meta-analyses were conducted to evaluate the overall relative risk and 95% confidence intervals in the combined studies for the assessment of primary outcome, which is the efficacy of bowel preparation with the addition of prucalopride.

RESULTS

Four randomized controlled trials involving 581 patients were included. When data were pooled for all patients in two non-inferiority studies, no significant difference in the quality of bowel preparation was observed between patients receiving prucalopride plus bowel preparation solution at a lower volume and those receiving the existing solution (relative risk: 0.94; 95% confidence interval: 0.86-1.03). The effects of prucalopride on acceptability, adverse events, adenoma detection rate, and polyp detection rate did not significantly differ from those of traditional solutions.

CONCLUSIONS

The combination of prucalopride and bowel preparation solution at a lower volume has similar effects on bowel preparation, and its use did not increase the occurrence of adverse effects.

Appropriate Use of Laxatives in the Older Person

Constipation is a common condition, affecting up to half of all older adults during their lifetime. Untreated constipation has significant impacts, decreasing quality of life and potentially leading to urinary and/or faecal incontinence, faecal impaction and, in severe cases, hospitalisation. The increased constipation prevalence among older populations is multifactorial, with a number of age-related factors contributing to the rise in prevalence with aging. Laxatives are the mainstay of constipation management and are commonly used among older populations for both treatment and prevention of constipation. A range of laxative types including bulk forming agents, softeners and emollients, osmotic agents, stimulants, and the newer prokinetic and secretory agents are available. Despite laxatives being freely available without prescription in many countries and commonly used by older individuals, evidence regarding the effectiveness or safety of most laxatives in older populations is lacking. Additionally, age-related changes increase the risk of adverse effects associated with laxatives, such as electrolyte disturbances, among older persons. Caution must be taken when extrapolating recommendations for general adult populations to older populations. Laxative choice for older individuals should be tailored after careful assessment and consideration of comorbid conditions, concomitant medications and the potential for adverse effects.

Prucalopride in Gastroparesis: A Randomized Placebo-Controlled Crossover Study

OBJECTIVES

Prokinetics are considered the preferred treatment option for gastroparesis, but evidence of their efficacy is scarce. Prucalopride, a selective 5-hydroxytryptamine 4 receptor agonist used in the treatment of constipation, is able to enhance the gastric emptying rate. In a double-blind, randomized, placebo-controlled crossover study, we evaluated the efficacy of prucalopride to improve the gastric emptying rate and symptoms in patients with gastroparesis.

METHODS

Thirty-four patients with gastroparesis (28 idiopathic, 7 men, mean age 42 ± 13 years) were evaluated in a double-blind crossover trial of 4-week treatment periods with placebo or prucalopride 2 mg q.d., separated by 2 weeks of washout. The primary end point was the change in symptom severity, assessed by the Gastroparesis Cardinal Symptom Index; secondary end points comprised the Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index, the Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life, and daily diaries, and the gastric emptying rate was assessed by the C-octanoic acid breath test.

RESULTS

Three patients were lost to follow-up. One serious adverse event occurred (small bowel volvulus in the prucalopride group), and 3 patients dropped out because of adverse events of nausea and headache (all prucalopride). For the entire patient group, compared with placebo, prucalopride significantly improved the total Gastroparesis Cardinal Symptom Index (1.65 ± 0.19 vs 2.28 ± 0.20, P < 0.0001) and the subscales of fullness/satiety, nausea/vomiting, and bloating/distention. Prucalopride significantly improved the overall Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life score (1.15 ± 0.16 vs 1.44 ± 0.16, P < 0.05) and the domains of clothing and diet. The gastric half emptying time was significantly enhanced by prucalopride compared with placebo and baseline (98 ± 10 vs 143 ± 11 and 126 ± 13 minutes, P = 0.005 and <0.001, respectively). These significant improvements were also found when considering only the idiopathic gastroparesis subgroup.

DISCUSSION

In a cohort of patients with predominantly idiopathic gastroparesis, 4 weeks of prucalopride treatment significantly improved symptoms and quality of life and enhanced gastric emptying compared with placebo.

Use of prucalopride in adults with chronic idiopathic constipation

Introduction: Prucalopride is a selective 5-HT₄ receptor agonist with colonic prokinetic activity. It was recently approved by the FDA for the treatment of chronic idiopathic constipation. Before this approval, there were limited options to improve colonic motility in the treatment of chronic idiopathic constipation. Areas covered: We systematically searched PubMed, Embase, ClinicalTrials.gov, and international conference presentations, and we reviewed all studies that evaluated prucalopride for the treatment of chronic idiopathic constipation in adults. In this review, we discuss the pharmacokinetics, pharmacodynamics, receptor interactions, phase I-IV clinical trials, and safety outcomes of prucalopride in adults, including the elderly. Expert opinion: Prucalopride is an effective agent to improve colonic motility, decrease colonic transit time, and increase complete spontaneous bowel movements in patients with chronic idiopathic constipation. Unlike previously available 5-HT₄ receptor agonists such as cisapride and tegaserod, prucalopride does not interact with the cardiac hERG potassium channels or other serotonergic receptors in blood vessels and is not associated with an increase in major adverse cardiovascular events. Additionally, prucalopride has demonstrated promise in the treatment of gastroparesis, post-operative ileus, and opioid-induced constipation. Prucalopride directly stimulates colonic motility, differentiating it from all other medications (exclusively osmotic or chloride secretagogues) approved for chronic constipation in the last decade.

Clinical Efficacy and Safety Profile of Prucalopride in Chronic Idiopathic Constipation

Chronic idiopathic constipation (CIC) can be defined as bowel movements that are difficult to pass, are not occurring frequently, or have incomplete evacuation during defecation. A high-fiber diet and laxatives are the commonly used treatments, but in many cases, they do not produce satisfactory results. The first line of treatment is osmotic laxatives. If there is no improvement, the second line is guanylate cyclase-C (GCC) agonists like linaclotide or prokinetic agents such as prucalopride. On December 14, 2018, the United States Food and Drug Administration (US FDA) approved prucalopride for treating chronic idiopathic constipation. Prucalopride is a prokinetic agent which works at the 5-hydroxytryptamine receptor 4 (5-HT4) as an agonist with greater receptor selectivity. Patients on prucalopride reported improved symptoms, quality of life and satisfaction. The most frequent adverse events were headaches and problems related to the gastrointestinal tract. Caution should be taken when using prucalopride in patients with impaired liver and renal function. In Canada, prucalopride has been approved for treatment of female patients with chronic idiopathic constipation who have failed therapy with at least two laxatives from different classes over a six-month period.

Recent advances in understanding and managing chronic constipation

Constipation, a condition characterized by heterogeneous symptoms, is common in Western society. It is associated with reduced physical health, mental health, and social functioning. Because constipation is rarely due to a life-threatening disease (for example, colon cancer), current guidelines recommend empiric therapy. Limited surveys suggest that fewer than half of treated individuals are satisfied with treatment, perhaps because the efficacy of drugs is limited, they are associated with undesirable side effects, or they may not target the underlying pathophysiology. For example, although a substantial proportion of constipated patients have a defecatory disorder that is more appropriately treated with pelvic floor biofeedback therapy than with laxatives, virtually no pharmacological trials formally assessed for anorectal dysfunction. Recent advances in investigational tools have improved our understanding of the physiology and pathophysiology of colonic and defecatory functions. In particular, colonic and anorectal high-resolution manometry are now available. High-resolution anorectal manometry, which is increasingly used in clinical practice, at least in the United States, provides a refined assessment of anorectal pressures and may uncover structural abnormalities. Advances in our understanding of colonic molecular physiology have led to the development of new therapeutic agents (such as secretagogues, pro-kinetics, inhibitors of bile acid transporters and ion exchangers). However, because clinical trials compare these newer agents with placebo, their efficacy relative to traditional laxatives is unknown. This article reviews these physiologic, diagnostic, and therapeutic advances and focuses particularly on newer therapeutic agents.

Cardiovascular effects of cisapride and prucalopride on human 5-HT4 receptors in transgenic mice

Cisapride and prucalopride act as 5-HT₄ receptor agonists. As a part of our ongoing effort to study the utility of a transgenic (TG) mouse model overexpressing cardiac 5-HT₄ receptors, we assessed the extent to which we could recapitulate cisapride and prucalopride agonists. Contractile studies were performed using isolated left and right atrial preparations of TG mice showing cardiac-specific human 5-HT_4a receptor expression and those of their wild-type (WT) littermates. 5-Hydroxytryptamine (5-HT), cisapride, and prucalopride exerted concentration-dependent positive inotropic effects in the left atrial preparations of TG mice. Moreover, 5-HT induced concentration-dependent arrhythmias in the right atrial preparations of TG mice starting from 10-nM concentration. However, cisapride induced arrhythmias not only in the right atrial preparations of TG mice but also in the right atrial preparations of WT mice. For instance, 10 μM cisapride induced arrhythmias in the right atrial preparations of TG and WT mice to the same extent. Prucalopride did not exert concentration-dependent proarrhythmic effects in the isolated atrial preparations (left or right, WT or TG). Furthermore, cisapride and prucalopride increased the contractility and beating rate in vivo in TG mice, as assessed by performing echocardiography and surface electrocardiography. In summary, our results indicate that cisapride and prucalopride increase contractility and beating rate in the isolated atrial preparations of TG mice or in intact TG mice. Moreover, 5-HT induced arrhythmias in the isolated right atrial preparations of TG mice in a concentration-dependent manner. Furthermore, cisapride induced arrhythmias in the isolated right atrial preparations of both TG and WT mice. In contrast, prucalopride did not induce arrhythmias in the atrial preparations (left or right) of both WT and TG mice. We suggest that the present TG mouse model might be useful to predict at least some important cardiac effects of 5-HT₄ receptor agonists in the human heart.

Expert consensus on the assessment and treatment of chronic constipation in the elderly

It is of significant importance to scientifically assess and efficiently address chronic constipation in the elderly population. Therefore, organizing some domestic experts of geriatrics and gastroenterology, we have formulated this consensus to reference for clinical staff.

The in vitro pharmacology and non-clinical cardiovascular safety studies of a novel 5-HT4 receptor agonist, DSP-6952

The pharmacological activity of DSP-6952, a novel compound was investigated, compared to that of clinically efficacious gastrointestinal (GI) prokinetic 5-hydroxytryptamine₄ (5-HT₄) receptor agonists. DSP-6952 had a strong affinity of Ki = 51.9 nM for 5-HT_4(b) receptor, and produced contraction in the isolated guinea pig colon with EC₅₀ of 271.6 nM and low intrinsic activity of 57%, similar to tegaserod and mosapride. In the development of the 5-HT₄ receptor agonists, cardiovascular risk was deliberately evaluated, because some related prokinetics were reported to cause with cardiovascular adverse events, such as ventricular arrhythmias or ischemia. DSP-6952 showed minimal effects up to 100 μM in human ether-a-go-go-related gene (hERG) channels or guinea pig cardiomyocytes. In telemetered conscious monkeys, DSP-6952 did not affect blood pressure or any electrocardiogram (ECG) up to 180 mg/kg, p.o.; however, DSP-6952 transiently increased heart rate, as well as in anesthetized dogs. The positive chronotropic effects of DSP-6952 were completely antagonized by a 5-HT₄ receptor antagonist, and another 5-HT₄ receptor agonist, TD-5108 also increased heart rate. These effects are considered a class effect seen in clinically developing and marketed 5-HT₄ receptor agonists, and have not been regarded as a critical issue in clinical use. DSP-6952 did not induce contraction in the rabbit coronary artery up to 100 μM, which differed from tegaserod or sumatriptan. These results show that DSP-6952 does not have cardiac ischemic risk via coronary vasoconstriction. In conclusion, DSP-6952 is a promising GI prokinetic compound with partial 5-HT₄ receptor agonistic activity as well as a favorable cardiovascular safety profile.

Synergy between 5-HT4 receptor stimulation and phosphodiesterase 4 inhibition in facilitating acetylcholine release in human large intestinal circular muscle

BACKGROUND

Gastroprokinetic properties of 5-HT₄ receptor agonists, such as prucalopride, are attributed to activation of 5-HT₄ receptors on cholinergic nerves innervating smooth muscle in the gastrointestinal smooth muscle layer, increasing acetylcholine release and muscle contraction. In porcine stomach and colon, phosphodiesterase (PDE) 4 has been shown to control the signaling pathway of these 5-HT₄ receptors. The aim of this study was to investigate the PDE-mediated control of these 5-HT₄ receptors in human large intestine.

METHODS

Circular smooth muscle strips were prepared from human large intestine; after incubation with [³H]-choline, electrically induced tritium outflow was determined as a measure for acetylcholine release. The influence of PDE inhibition on the facilitating effect of prucalopride on electrically induced acetylcholine release was studied.

KEY RESULTS

The non-selective PDE inhibitor IBMX enhanced the facilitating effect of prucalopride on electrically induced acetylcholine release. The selective inhibitors vinpocetine (PDE1), EHNA (PDE2) and cilostamide (PDE3) did not influence, while rolipram and roflumilast (PDE4) enhanced the prucalopride-induced facilitation to the same extent as IBMX.

CONCLUSIONS & INFERENCES

In human large intestinal circular muscle, the intracellular pathway of 5-HT₄ receptors facilitating cholinergic neurotransmission to large intestinal circular smooth muscle is controlled by PDE4. If the synergy between 5-HT₄ receptor agonism and PDE4 inhibition is confirmed in a functional assay with electrically induced cholinergic contractions of human large intestinal circular smooth muscle strips, combination of a selective 5-HT₄ receptor agonist with a selective PDE4 inhibitor might enhance the in vivo prokinetic effect of the 5-HT₄ receptor agonist in the large intestine.

An update on prucalopride in the treatment of chronic constipation

Chronic constipation (CC) is a highly prevalent and often under-appreciated gastrointestinal disorder associated with significant impairment in quality of life. Symptoms of constipation are typically present for a number of years prior to a patient seeking help. Lifestyle modifications followed by, or coupled with, over-the-counter laxatives represent the initial treatment option; however, relief for many is limited and dissatisfaction rates for these approaches remain high. Over recent years, therefore, considerable effort has been exerted on the development of novel pharmacological approaches. Two major targets have emerged, motility and secretion. Research on the former led to the development of a number of prokinetic agents capable of stimulating colonic motility and, thus, accelerating colonic transit. Of these, earlier prototypes such as cisapride and tegaserod, though effective, were ultimately withdrawn due to cardiovascular adverse events due in part to receptor non-selectivity. Highly selective serotonergic receptor agonists have since emerged which appear to be equally effective in stimulating gut motility but are devoid of cardiac side effects. One such agent is prucalopride, which has now been approved for the management of chronic idiopathic constipation in several countries, but not in the United States. Multiple multicenter, randomized placebo-controlled clinical trials have demonstrated superiority for prucalopride compared to placebo in the short to medium term in relieving the major symptoms of constipation in both men and women across a broad spectrum of ages, ethnicities and geographic locations. To date, prucalopride has enjoyed a favorable safety profile and there have been no signals to suggest arrythmogenicity. Efficacy over longer periods of treatment remains to be confirmed. Evidence for efficacy in other forms of constipation, such as opioid-induced constipation and that related to Parkinson's disease is beginning to emerge; its status in the management of constipation-predominant irritable bowel syndrome or foregut motility disorders, such as gastroparesis, remains to be established.

New therapeutic perspectives in irritable bowel syndrome: Targeting low-grade inflammation, immuno-neuroendocrine axis, motility, secretion and beyond

Irritable bowel syndrome (IBS) is a chronic, recurring, and remitting functional disorder of the gastrointestinal tract characterized by abdominal pain, distention, and changes in bowel habits. Although there are several drugs for IBS, effective and approved treatments for one or more of the symptoms for various IBS subtypes are needed. Improved understanding of pathophysiological mechanisms such as the role of impaired bile acid metabolism, neurohormonal regulation, immune dysfunction, the epithelial barrier and the secretory properties of the gut has led to advancements in the treatment of IBS. With regards to therapies for restoring intestinal permeability, multiple studies with prebiotics and probiotics are ongoing, even if to date their efficacy has been limited. In parallel, much progress has been made in targeting low-grade inflammation, especially through the introduction of drugs such as mesalazine and rifaximin, even if a better knowledge of the mechanisms underlying the low-grade inflammation in IBS may allow the design of clinical trials that test the efficacy and safety of such drugs. This literature review aims to summarize the findings related to new and investigational therapeutic agents for IBS, most recently developed in preclinical as well as Phase 1 and Phase 2 clinical studies.

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.

The possible role of gastrointestinal endocrine cells in the pathophysiology of irritable bowel syndrome

The etiology of irritable bowel syndrome (IBS) is unknown, but several factors appear to play a role in its pathophysiology, including abnormalities of the gastrointestinal endocrine cells. The present review illuminates the possible role of gastrointestinal hormones in the pathophysiology of IBS and the possibility of utilizing the current knowledge in treating the disease. Areas covered: Research into the intestinal endocrine cells and their possible role in the pathophysiology of IBS is discussed. Furthermore, the mechanisms underlying the abnormalities in the gastrointestinal endocrine cells in IBS patients are revealed. Expert commentary: The abnormalities observed in the gastrointestinal endocrine cells in IBS patients explains their visceral hypersensitivity, gastrointestinal dysmotility, and abnormal intestinal secretion, as well as the interchangeability of symptoms over time. Clarifying the role of the intestinal stem cells in the pathophysiology of IBS may lead to new treatment methods for IBS.

Pharmacological treatment for antipsychotic-related constipation

BACKGROUND

Antipsychotic-related constipation is a common and serious adverse effect, especially for people taking clozapine. Clozapine has been shown to impede gastrointestinal motility, leading to constipation, and has been reported in up to 60% of patients receiving clozapine. In rare cases, complications can be fatal. Appropriate laxatives should be prescribed to treat constipation in people taking antipsychotics, but there is a lack of guidance on the comparative effectiveness and harms of different agents in this population. An understanding of the effectiveness and safety of treatment for antipsychotic-related constipation is important for clinicians and patients alike.

OBJECTIVES

To evaluate the effectiveness and safety of pharmacologic treatment (versus placebo or compared against another treatment) for antipsychotic-related constipation (defined as constipated patients of any age, who are treated with antipsychotics, regardless of dose, in which constipation is considered to be an antipsychotic-related side effect).

SEARCH METHODS

We searched the Cochrane Schizophrenia Group's Trials Register (15 June 2015), which is based on regular searches of MEDLINE, Embase, CINAHL, BIOSIS, AMED, PubMed, PsycINFO, and registries of clinical trials, grey literature, and conference proceedings. There are no language, date, document type, or publication status limitations for inclusion of records in this register. We also handsearched bibliographies and contacted relevant authors for additional information.

SELECTION CRITERIA

We included all published and unpublished randomised controlled trials (RCTs) investigating the efficacy of pharmacological treatments in patients with antipsychotic-related constipation. Pharmacological treatments included laxatives and other medicines that could reasonably be used to combat constipation in this population (e.g. anticholinergic agents, like bethanecol).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from all included studies and assessed trials for risk of bias. A third author reviewed 20% of trials. We analysed dichotomous data using relative risks (RR) and the 95% confidence intervals (CI). We assessed risk of bias for included studies and used GRADE to create a 'Summary of findings' table. We discussed any disagreement, documented decisions, and attempted to contact study authors when necessary.

MAIN RESULTS

We identified two relevant Chinese studies (N = 480) that contributed data to this review. Both studies were over ten years old and poorly reported, lacking descriptions of contemporary CONSORT reporting prerequisites, such as sequence generation, allocation concealment, blinding, participant flow, how the sample size was determined, or how outcomes were measured. The studies also did not report trial registration, pre-specified protocols, consent processes, ethical review, or funding source. We were unsuccessful in making contact with the authors to clarify the missing details. We classified both studies as having an overall high risk of bias.One study compared glycerol suppository with the traditional Chinese medicine (TCM) approaches of tuina massage and acupuncture. Compared to tuina massage, glycerol laxative was less effective in relieving constipation at both two days after treatment (1 RCT; N = 120; RR 2.88, 95% CI 1.89 to 4.39; very low-quality evidence), and three days (1 RCT; N = 120; RR 4.80, CI 1.96 to 11.74, very low-quality evidence). Favourable results were also seen for acupuncture at two days (1 RCT; N = 120; RR 3.50; 95% CI 2.18 to 5.62; very low-quality evidence), and at three days (1 RCT; N = 120; RR 8.00, 95% CI 2.54 to 25.16; very low-quality evidence).The other study compared mannitol, an osmotic laxative, with rhubarb soda or phenolphthalein. Mannitol was more effective than rhubarb soda or phenolphthalein in trelieving constipation within 24 hours of treatment (1 RCT; N = 240; RR 0.07; 95% CI 0.02 to 0.27, very low-quality evidence).No data were reported for our other important outcomes: need for rescue medication, bowel obstruction (a complication of antipsychotic-related constipation), quality of life, adverse events, leaving the study early, and economic costs.

AUTHORS' CONCLUSIONS

We had hoped to find clinically useful evidence appraising the relative merits of the interventions routinely used to manage antipsychotic-related constipation, a common and potentially serious adverse effect of the use of these drugs. The results were disappointing. There were no data comparing the common pharmacological interventions for constipation, such as lactulose, polyethylene glycol, stool softeners, lubricant laxatives, or of novel treatments such as linaclotide. Data available were very poor quality and the trials had a high risk of bias. Data from these biased studies suggested that mannitol, an osmotic laxative, was more effective than rhubarb soda and phenolphthalein in relieving constipation, and a two-week course of glycerol suppositories was less effective than the TCM approaches of tuina massage and acupuncture.Overall, there is insufficient trial-based evidence to assess the effectiveness and safety of pharmacological interventions for treating antipsychotic-related constipation, due to limited, poor quality data (few studies with high risk of bias and no meta-analyses). The methodological limitations in the included studies were obvious, and any conclusions based on their results should be made with caution. Methodologically rigorous RCTs evaluating interventions for treating antipsychotic-related constipation are needed.

Prucalopride succinate for the treatment of constipation: an update

Constipation is a disorder frequently complained about by patients in daily clinical practice. However, to date, its treatment is still commonly unsatisfactory, especially concerning patients' quality of life, when using conventional measures. Prucalopride, a selective 5-hydroxytryptamine receptor 4 agonist, was introduced to the market in 2009 and has been commercially available in Europe since 2010. The main effect of prucalopride is to stimulate colonic motility, which explains its efficacy to treat constipated patients unresponsive to other regimens. Literature search was carried out to look for effects of prucalopride on constipated patients. Several papers were found demonstrating that prucalopride is effective in treatment of constipated patients. Due to its few side effects, the lack of cardiovascular effects and interactions with other drugs, prucalopride may be safely used in elderly people as well.

Development and validation of a sensitive UHPLC-MS/MS method for quantitation of prucalopride in rat plasma and its application to pharmacokinetics study

A rapid, sensitive, selective and accurate ultra high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the quantitation of prucalopride in rat plasma using carbamazepine as an internal standard (IS). Separation was achieved on a Waters ACQUITY UHPLC(®) HSS C18 column (2.1mm×50mm, 1.8μm) column with a gradient mobile phase consisting of acetonitrile-water (containing 0.1% formic acid) as mobile phase at a flow rate of 0.2mL/min. Prucalopride and IS were monitored using positive electrospray triple quadrupole mass spectrometer (Waters Xevo TQD) via multiple reaction monitoring (MRM) mode. The monitored transitions were set at m/z 367.99→195.89 and m/z 236.97→194.04 for prucalopride and IS, respectively. The achieved lower limit of quantitation was 0.1ng/mL. The validated method had an excellent linearity in the range of 0.1-100ng/mL (r>0.996). The intra- and inter-day precisions were both≤7.8% for prucalopride and IS, and the average intra- and inter-day accuracies ranged from -3.0% to 8.5%. Extraction recoveries at three levels QC concentrations were in the range of 90.0-110.0% for prucalopride and 99.6% for IS. Matrix effects were found to be acceptable. The validated assay was successfully applied to a pharmacokinetic study of prucalopride following oral administration of 0.25, 0.5, 1.0mg/kg to female and male rats respectively.

Use of Prucalopride for Chronic Constipation: A Systematic Review and Meta-analysis of Published Randomized, Controlled Trials

This article highlights the role of prucalopride in the management of chronic constipation based upon the principles of meta-analysis using data reported in the published randomized, controlled trials. Sixteen randomized, controlled trials on 3943 patients reported the effectiveness of prucalopride in patients with chronic constipation. Prucalopride successfully increased the frequency of spontaneous bowel movements per week in all variable doses of 1 mg (standardized mean difference [SMD], 0.42 [95% CI, 0.18-0.66; P = 0.006]), 2 mg (SMD, 0.34 [95% CI, 0.11-0.56; P = 0.003]), and 4 mg (SMD, 0.33 [95% CI, 0.22-0.44; P = 0.00001]). The risks of adverse events or side effects such as headache, abdominal cramps, excessive flatulence, dizziness, diarrhea, and rash were higher (odds ratio, 1.70 [95% CI, 1.27 to -2.27; P = 0.0004]) in prucalopride group. Prucalopride is clinically a beneficial pharmacotherapy for chronic constipation and its routine use may be considered in patients with chronic simple laxative-resistant constipation.

Patient considerations in the management of chronic constipation: focus on prucalopride

Chronic constipation is a common condition that significantly impacts health care utilization, productivity, and quality of life. Laxatives are commonly used, although often insufficient in restoring normal bowel function or providing adequate relief. There remains a significant need for the development of novel agents to optimize treatment of this condition. This review provides an overview of the preclinical and clinical trial data, supporting the efficacy and safety of prucalopride, a highly selective 5-HT4 receptor agonist that has been approved by the European Medicine Agency for the treatment of chronic constipation in adults who have failed standard laxative therapy. Unlike older 5-HT4 agonists, prucalopride has not been associated with adverse cardiovascular side effects or QT prolongation owing to its high selectivity and affinity for the 5-HT4 receptor without clinically significant cross-reactivity at the human ether-à-go-go-related gene (hERG) potassium channel or 5-HT receptor subtypes that have previously been implicated in adverse cardiovascular events and arrhythmias. Careful safety assessments have documented the relative safety and tolerability of this agent in various patient groups. Focus has also been placed on demonstrating efficacy with regard to bowel function, symptoms, and patient-reported outcomes such as the Patient Assessment of Constipation-Symptoms and the Patient Assessment of Constipation Quality of Life scores to support the use of prucalopride as a safe and effective therapeutic option for the management of chronic constipation.

Review of efficacy and safety of laxatives use in geriatrics

AIM: To study the efficacy and safety of pharmacological treatment of constipation in geriatrics.

METHODS: PubMed, MEDLINE, google scholar, and Ovid were searched to identify human studies performed on the use of laxatives in elderly with constipation, which were conducted between January 1990 and January 2013 using the specified keywords. Controlled studies that enrolled geriatric patients with a diagnosis of constipation and addressed the efficacy and/or the safety of pharmacological treatments were included. Studies were excluded from this review if they were non-controlled trials, case series, or case reports.

RESULTS: Out of twenty three studies we initially retrieved in our search, only nine studies met the eligibility criteria of being controlled trials within geriatrics. The laxatives examined in the nine studies were senna, lactulose, sorbital, polyethylene glycol (PEG), lubiprostone, linaclotide, and prucalopride. In those studies, senna combinations had a higher efficacy than sorbitol or lactulose as well as, a very good adverse effect profile. PEG was also shown to be safe and effective in geriatric population. Furthermore, it has been shown that PEG is as safe in geriatrics as in general population. New agents like lubiprostone and prucalopride show promising results but the data about these agents in geriatrics are still limited which warrants further investigation.

CONCLUSION: Senna combinations and PEG appear to have a more favorable profile over the other traditionally used laxatives in elderly patients with constipation.

Randomised clinical trial: prucalopride, a colonic pro-motility agent, reduces the duration of post-operative ileus after elective gastrointestinal surgery

BACKGROUND

Previous studies have shown that recovery of colonic transit is a major determinant of post-operative ileus and clinical recovery after gastrointestinal surgery. Prucalopride is a highly selective 5-hydroxytryptamine receptor-4 agonist with colonic pro-motility effects.

AIM

To evaluate the effect and safety of prucalopride on post-operative ileus and surgical outcomes after elective gastrointestinal surgery.

METHODS

In this phase II randomised clinical trial, 110 patients undergoing elective gastrointestinal surgery were randomised to either oral prucalopride (2 mg/day) (n = 55) or placebo (n = 55). Intervention was started 24 h after surgery and stopped after defecation or maximally at 7 days. The primary outcome was time to defecation. Secondary outcomes included time to first passage of flatus, tolerance of solid food, nasogastric tube reinsertion, post-operative length of stay, hospital readmission, overall cost, time to walk independently, surgical complications and inflammatory parameters.

RESULTS

Patients who received prucalopride had a shorter time to defecation (65.0 vs. 94.5 h, P = 0.001), passage of flatus (53.0 vs. 73.0 h, P < 0.001), and post-operative length of stay (7.0 vs. 8.0 days, P = 0.001) than controls. The number of patients with prolonged ileus (>5 days) (16.4% vs. 34.5%, P = 0.026) and the C-reactive protein level on post-operative day 5 (35.67 vs. 59.07 mg/L, P = 0.040) were lower in the prucalopride group. There was no significant difference in post-operative Clavien-Dindo grade III and IV complications (P = 0.606) between the groups.

CONCLUSION

Prucalopride is a safe and effective treatment to reduce post-operative ileus and systemic inflammation without affecting post-operative complications in patients undergoing elective gastrointestinal surgery. ClinicalTrials.gov: NCT02004652.

Pharmacological, Pharmacokinetic, and Pharmacogenomic Aspects of Functional Gastrointestinal Disorders

This article reviews medications commonly used for the treatment of patients with functional gastrointestinal disorders. Specifically, we review the animal models that have been validated for the study of drug effects on sensation and motility; the preclinical pharmacology, pharmacokinetics, and toxicology usually required for introduction of new drugs; the biomarkers that are validated for studies of sensation and motility endpoints with experimental medications in humans; the pharmacogenomics applied to these medications and their relevance to the FGIDs; and the pharmacology of agents that are applied or have potential for the treatment of FGIDs, including psychopharmacologic drugs.

Factors predictive of treatment-emergent adverse events of prucalopride: an integrated analysis of four randomized, double-blind, placebo-controlled trials

Background/Aims

This integrated analysis aimed to identify the factors associated with the most frequently reported treatment-emergent adverse events (TEAEs) in Asian and non-Asian patients with chronic constipation (CC) who receive prucalopride or placebo over 12 weeks.

Methods

Pooled data from four randomized, double-blind, placebo-controlled, multicenter, phase III studies (NCT00488137, NCT00483886, NCT00485940, and NCT01116206) on patients treated with prucalopride 2 mg or placebo were analyzed. The associations between predictors and TEAEs were evaluated based on a logistic regression model.

Results

Overall, 1,821 patients (Asian, 26.1%; non-Asian, 73.9%) were analyzed. Prucalopride treatment was significantly associated with diarrhea, headache, and nausea (p<0.001), but not with abdominal pain, compared with placebo. Differences in the prevalence of TEAEs between prucalopride and placebo decreased greatly after the first day of treatment. Compared with non-Asians, Asians were more likely to experience diarrhea and less likely to develop abdominal pain, headache, and nausea. Prior laxative use, CC duration, and body weight were not predictive of any of these TEAEs.

Conclusions

Prucalopride treatment was positively associated with diarrhea, headache, and nausea. Asian patients tended to have a higher frequency of diarrhea but lower frequencies of headache, abdominal pain, and nausea compared with non-Asians.

Recent Updates on the Treatment of Constipation

The treatment of constipation aims to regulate the frequency and quantity of stool in order to promote successful defecation. Numerous studies on pharmacologic treatments and non-pharmacologic therapies for constipation have attempted to overcome limitations such as temporary and insufficient efficacy. Conventional laxatives have less adverse effects and are inexpensive, but often have limited efficacy. Recently developed enterokinetic agents and intestinal secretagogues have received attention owing to their high efficacies and low incidences of adverse events. Studies on biofeedback and surgical treatment have focused on improving symptoms as well as quality of life for patients with refractory constipation.

Chronic constipation in the elderly: a primer for the gastroenterologist

Constipation is a frequently reported bowel symptom in the elderly with considerable impact on quality of life and health expenses. Disease-related morbidity and even mortality have been reported in the affected frail elderly. Although constipation is not a physiologic consequence of normal aging, decreased mobility, medications, underlying diseases, and rectal sensory-motor dysfunction may all contribute to its increased prevalence in older adults. In the elderly there is usually more than one etiologic mechanism, requiring a multifactorial treatment approach. The majority of patients would respond to diet and lifestyle modifications reinforced by bowel training measures. In those not responding to conservative treatment, the approach needs to be tailored addressing all comorbid conditions. In the adult population, the management of constipation continues to evolve as well as the understanding of its complex etiology. However, the constipated elderly have been left behind while gastroenterology consultations for this common conditions are at a rise for the worldwide age increment. Aim of this review is to provide an update on epidemiology, quality of life burden, etiology, diagnosis, current approaches and limitations in the management of constipation in the older ones to ease the gastroenterologists’ clinic workload.

Current advances in treatment of gastroparesis

INTRODUCTION

Gastroparesis is a syndrome defined by delayed gastric emptying in the absence of mechanical obstruction. Gastroparesis has significant symptomatology and negative impacts on the patient's quality of life.

AREAS COVERED

This article reviews current treatment options for gastroparesis, recent advances in treatment and future directions that treatment may head. Current options are broadly divided into prokinetics and symptom modulators. Within each group, current modalities as well as recent advances are discussed according to agent mechanism of action. Lastly, findings regarding the cellular pathophysiology involved in gastroparesis will be briefly reviewed along with their implications for future treatments.

EXPERT OPINION

The numerous motor functions and neural inputs that control gastric motility are complex and not fully understood. Our lack of understanding of its pathophysiology has led to treatment options which are empirical, palliative and often ineffective. Newly intensified interest in the cellular pathophysiology behind gastroparesis provides promise for a new era of treatments. Identification of common cellular changes in gastroparesis has provided targets for treatment that may allow us to one day better treat the symptoms of gastroparesis related to its underlying pathophysiology. This is the future of gastroparesis therapy.

Epidemiology and management of chronic constipation in elderly patients

Constipation is a common functional gastrointestinal disorder, with prevalence in the general population of approximately 20%. In the elderly population the incidence of constipation is higher compared to the younger population, with elderly females suffering more often from severe constipation. Treatment options for chronic constipation (CC) include stool softeners, fiber supplements, osmotic and stimulant laxatives, and the secretagogues lubiprostone and linaclotide. Understanding the underlying etiology of CC is necessary to determine the most appropriate therapeutic option. Therefore, it is important to distinguish from pelvic floor dysfunction (PFD), slow and normal transit constipation. Evaluation of a patient with CC includes basic blood work, rectal examination, and appropriate testing to evaluate for PFD and slow transit constipation when indicated. Pelvic floor rehabilitation or biofeedback is the treatment of choice for PFD, and its efficacy has been proven in clinical trials. Surgery is rarely indicated in CC and can only be considered in cases of slow transit constipation when PFD has been properly excluded. Other treatment options such as sacral nerve stimulation seem to be helpful in patients with urinary dysfunction. Botulinum toxin injection for PFD cannot be recommended at this time with the available evidence. CC in the elderly is common, and it has a significant impact on quality of life and the use of health care resources. In the elderly, it is imperative to identify the etiology of CC, and treatment should be based on the patient’s overall clinical status and capabilities.

A randomized, double-blind, placebo-controlled, phase 3 trial to evaluate the efficacy, safety, and tolerability of prucalopride in men with chronic constipation

OBJECTIVES

Prucalopride is effective at alleviating symptoms of chronic constipation in women. The aim of this study was to assess the efficacy of 12 weeks of prucalopride treatment compared with placebo in men with chronic constipation.

METHODS

This was a multicenter, stratified, randomized, parallel-group, double-blind, placebo-controlled, phase 3 study (ClinicalTrials.gov identifier: NCT01147926). The primary end point was the proportion of patients with a mean of three or more spontaneous complete bowel movements (SCBMs) per week across the treatment period. Efficacy end points were assessed using daily electronic diaries, global assessment of the severity of constipation and efficacy of treatment, and Patient Assessment of Constipation-Symptoms (PAC-SYM) and Patient Assessment of Constipation-Quality of Life (PAC-QOL) questionnaires.

RESULTS

In total, 374 patients were enrolled in the study. Significantly more patients achieved a mean of three or more SCBMs per week in the prucalopride group (37.9%) than in the placebo group (17.7%, P<0.0001). The proportion of patients rating their constipation treatment as "quite a bit" to "extremely" effective at the final on-treatment visit was 46.7 and 30.4% in the prucalopride and placebo groups, respectively. The difference between treatment groups was statistically significant (P<0.0001). The proportion of patients with an improvement of at least 1 point in PAC-QOL satisfaction subscale score was 52.7 and 38.8% in the prucalopride and placebo groups, respectively (P=0.0035). Prucalopride had a good safety profile and was well tolerated.

CONCLUSIONS

Prucalopride is effective, has a good safety profile, and is well tolerated for the treatment of men with chronic constipation.

Efficacy and safety of prucalopride in adults and children with chronic constipation

INTRODUCTION

Chronic constipation (CC) is a debilitating condition with high prevalence rates both in children and adults. Despite the broad range of medical and pharmaceutical treatments, the bowel function does not restore in a fair amount of patients. Prucalopride is a first-in-class selective, high affinity serotonin 5-hydroxytryptamine type 4 (5-HT4) receptor agonist promoting gastro-intestinal prokinetic activity and has been evaluated for the treatment of CC.

AREAS COVERED

A PubMed search (1965 - 2014) using the following terms alone or in combination: prucalopride, 5-HT4, R093877, safety, toxicity, pharmacokinetics, pharmacodynamics, transit, cardiac, human ether-a-go-go related gene (hERG), arrhythmia, potassium current, elderly, children.

EXPERT OPINION

Prucalopride, a highly selective 5-HT4 receptor agonist, stimulates gastrointestinal motility and has been proven to be effective in the treatment of CC in adults by increasing stool frequency, reducing constipation-related symptoms and improving quality of life (QoL). The safety and tolerability have been proven to be excellent. More research would be preferable on the effect of prucalopride on men, children and in other gastrointestinal motility disorders.

Cholinergic interactions between donepezil and prucalopride in human colon: potential to treat severe intestinal dysmotility

BACKGROUND AND PURPOSE

Cholinesterase inhibitors such as neostigmine are used for acute colonic pseudo-obstruction, but cardio-bronchial side-effects limit use. To minimize side-effects, lower doses could be combined with a 5-HT4 receptor agonist, which also facilitates intestinal cholinergic activity. However, safety concerns, especially in the elderly, require drugs with good selectivity of action. These include the AChE inhibitor donepezil (used for Alzheimer's disease, with reduced cardio-bronchial liability) and prucalopride, the first selective, clinically available 5-HT4 receptor agonist. This study examined their individual and potential synergistic activities in human colon.

EXPERIMENTAL APPROACH

Neuronally mediated muscle contractions and relaxations of human colon were evoked by electrical field stimulation (EFS) and defined phenotypically as cholinergic, nitrergic or tachykinergic using pharmacological tools; the effects of drugs were determined as changes in 'area under the curve'.

KEY RESULTS

Prucalopride increased cholinergically mediated contractions (EC50 855 nM; 33% maximum increase), consistent with its ability to stimulate intestinal motility; donepezil (477%) and neostigmine (2326%) had greater efficacy. Concentrations of donepezil (30-100 nM) found in venous plasma after therapeutic doses had minimal ability to enhance cholinergic activity. However, donepezil (30 nM) together with prucalopride (3, 10 μM) markedly increased EFS-evoked contractions compared with prucalopride alone (P = 0.04). For example, the increases observed with donepezil and prucalopride 10 μM together or alone were, respectively, 105 ± 35%, 4 ± 6% and 35 ± 21% (n = 3-7, each concentration).

CONCLUSIONS AND IMPLICATIONS

Potential synergy between prucalopride and donepezil activity calls for exploration of this combination as a safer, more effective treatment of colonic pseudo-obstruction.

Prucalopride-associated acute tubular necrosis

We report the first case of acute renal failure secondary to prucalopride, a novel agent for the treatment of chronic constipation. The 75 years old male patient was initiated on prucalopride after many failed treatments for constipation following a Whipple’s procedure for pancreatic cancer. Within four months of treatment his creatinine rose from 103 to 285 μmol/L (eGFR 61 decrease to 19 mL/min per 1.73 m²). He was initially treated with prednisone for presumed acute interstitial nephritis as white blood casts were seen on urine microscopy. When no improvement was detected, a core biopsy was performed and revealed interstitial fibrosis and tubular atrophy. The presence of oxalate and calcium phosphate crystals were also noted. These findings suggest acute tubular necrosis which may have been secondary to acute interstitial nephritis or hemodynamic insult. The use of prednisone may have suppressed signs of inflammation and therefore the clinical diagnosis was deemed acute interstitial nephritis causing acute tubular necrosis. There are no previous reports of prucalopride associated with acute renal failure from the literature, including previous Phase II and III trials.

Prucalopride: a review of its use in the management of chronic constipation

The highly selective serotonin 5-HT4 receptor agonist prucalopride (Resolor(®), Resotran(®), Resotrans(®)) is indicated for the treatment of chronic constipation. In four randomized, double-blind, multicentre, 12-week trials in patients (predominantly women) with chronic constipation, oral prucalopride 2 mg once daily improved bowel function to a significantly greater extent than placebo, with a significantly greater proportion of prucalopride than placebo recipients achieving an average of ≥3 spontaneous, complete bowel movements per week (primary endpoint). Significantly greater improvements in health-related quality of life, patient satisfaction with treatment and bowel habit, and a range of constipation-related symptoms were also seen with prucalopride than with placebo. Satisfaction with treatment and bowel habit was maintained with prucalopride in the longer term. Prucalopride was generally well tolerated in patients with chronic constipation, with the most commonly reported adverse events (headache, nausea, abdominal pain, diarrhoea) primarily occurring on the first day of treatment. During the clinical trials, no cardiovascular safety issues have arisen in patients with chronic constipation receiving prucalopride. In conclusion, prucalopride is an important option for use in patients with chronic constipation who have not experienced adequate relief with laxatives.

Understanding and treating refractory constipation

Chronic constipation is a frequently encountered disorder in clinical practice. Most constipated patients benefit from standard medical approaches. However, current therapies may fail in a proportion of patients. These patients deserve better evaluation and thorough investigations before their labeling as refractory to treatment. Indeed, several cases of apparent refractoriness are actually due to misconceptions about constipation, poor basal evaluation (inability to recognize secondary causes of constipation, use of constipating drugs) or inadequate therapeutic regimens. After a careful re-evaluation that takes into account the above factors, a certain percentage of patients can be defined as being actually resistant to first-line medical treatments. These subjects should firstly undergo specific diagnostic examination to ascertain the subtype of constipation. The subsequent therapeutic approach should be then tailored according to their underlying dysfunction. Slow transit patients could benefit from a more robust medical treatment, based on stimulant laxatives (or their combination with osmotic laxatives, particularly over the short-term), enterokinetics (such as prucalopride) or secretagogues (such as lubiprostone or linaclotide). Patients complaining of obstructed defecation are less likely to show a response to medical treatment and might benefit from biofeedback, when available. When all medical treatments prove to be unsatisfactory, other approaches may be attempted in selected patients (sacral neuromodulation, local injection of botulinum toxin, anterograde continence enemas), although with largely unpredictable outcomes. A further although irreversible step is surgery (subtotal colectomy with ileorectal anastomosis or stapled transanal rectal resection), which may confer some benefit to a few patients with refractoriness to medical treatments.