prucalopride and tegaserod

Chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (C-IBS) are commonly reported gastrointestinal (GI) disorders that have a major impact on health and quality of life. Patients experience a range of symptoms of which infrequency of bowel movement is but one and report that straining, the production of hard stools, and unproductive urges are more bothersome than stool infrequency. Additionally, in C-IBS, patients report abdominal pain and bloating as particularly troubling. Traditional treatments, such as laxatives, are often ineffective, especially in more severe constipation over the long term. In a population-based survey of constipation sufferers, half were not satisfied with their current treatment, due predominantly to poor efficacy. 5-Hydroxytryptamine receptor 4 (5-HT4) agonists stimulate GI motility and intestinal secretion, and tegaserod has demonstrated efficacy in improving bowel habit. Tegaserod also improves constipation-associated symptoms including bloating, abdominal discomfort, stool consistency, and straining in patients with both CIC and C-IBS. However, tegaserod has been withdrawn due to an association with serious adverse cardiovascular effects. Further 5-HT(4) receptor agonists, including prucalopride and TD-5108 are in development and show exciting results in clinical studies in CIC patients, suggesting further product approvals are likely. Headache and diarrhea are the most commonly reported adverse event with this class of agent. Recently a novel prosecretory agent has been approved for the treatment of both CIC and C-IBS. Lubiprostone stimulates chloride secretion through activation of type-2 chloride channels, increasing intestinal secretion and transit, and its use has been associated with improvements in bowel habit and symptoms of constipation. Nausea, diarrhea, and headache are the most commonly reported adverse events. Linaclotide also stimulates intestinal chloride secretion, but this molecule achieves this indirectly, through the activation of guanylate cyclase C. Data are emerging, but the efficacy and safety profile of this agent in the treatment of CIC and C-IBS appears encouraging.

Topics: Alprostadil; Azabicyclo Compounds; Benzofurans; Chloride Channels; Chronic Disease; Constipation; Gastrointestinal Agents; Gastrointestinal Motility; Guanylate Cyclase; Humans; Indoles; Irritable Bowel Syndrome; Laxatives; Lubiprostone; Peptides; Safety; Serotonin 5-HT4 Receptor Agonists; Serotonin Receptor Agonists; Treatment Outcome

Topics: Antidepressive Agents; Benzofurans; Carbazoles; Carbolines; Colonic Diseases, Functional; Gastrointestinal Agents; Humans; Indoles; Physical Examination; Pyridines

Gastrointestinal motility disorders represent a diagnostic and therapeutic challenge. Disorders of gastrointestinal motility may result in accelerated transit, delayed transit, impaired relaxation, or inappropriate relaxation. The delayed transit disorders are the most important motility disorders of companion animals and may involve the esophagus (hypomotility and megaesophagus), stomach (delayed gastric emptying), small intestine (postoperative ileus and intestinal pseudo-obstruction), or colon (constipation and megacolon).

Topics: Animals; Benzofurans; Cisapride; Dog Diseases; Dogs; Gastrointestinal Agents; Gastrointestinal Motility; Indoles; Intestinal Diseases; Motilin

Functional gastrointestinal disorders are characterised by central and peripheral physiological changes, associated with psychological factors. Successful drug development has been hindered by lack of adequate characterisation of the nature of symptoms and their physiological and psychological correlates. Animal models of chronic stress are lacking. High levels of drug safety are now demanded for treating non-life threatening conditions. Once close to market, patient pressure groups, health care providers and insurers, government, and the internet can all influence a drug's success. Serotonin-modifying drugs have been the main recent focus of development, with mixed results. Cisapride has been withdrawn because of concerns related to QT prolongation and cardiac arrhythmias. The 5-HT3 antagonists have been developed on the questionable assumption that they modify visceral sensation in patients. Problems have arisen with alosetron being associated with ischaemic colitis and a high incidence of constipation. The 5-HT4 agonists have their major effect on inducing peristalsis, and may modify gut secretion and sensory function. Tegaserod and prucalopride show promise in patients with constipation and related symptoms. 5-HT1 agonists may play a role in treating functional dyspepsia, partly by improving impaired gastric accommodation to a meal. Antidepressants, often found to be clinically beneficial in these disorders, also affect serotonin metabolism. Past successes, such as loperamide or the somatostatin analogue octreotide, involved targeting end organ receptors influencing motor function or secretion. Modifying sensory function is much more challenging. Future research with novel compounds need to keep these recent lessons in mind.

Topics: Antidepressive Agents; Benzofurans; Carbolines; Cisapride; Constipation; Drug Industry; Gastrointestinal Agents; Humans; Indoles; Irritable Bowel Syndrome; Serotonin 5-HT3 Receptor Antagonists; Serotonin 5-HT4 Receptor Agonists; Serotonin Antagonists; Serotonin Receptor Agonists

Existing pharmacotherapeutic options for the treatment of patients with irritable bowel syndrome (IBS) are limited in treating the multiple symptoms associated with the disorder. There is much interest in the use of serotonin agents as new therapeutics. Acting primarily through 5-HT3 and 5-HT4 receptors, serotonin elicits changes in motor function and possibly visceral sensation. Two serotonin agents were developed specifically for IBS: tegaserod, a 5-HT4 receptor partial agonist, and alosetron, a 5-HT3 receptor antagonist (which is no longer available). Phase III clinical trial data show that during a 12-week treatment period with tegaserod, IBS patients with abdominal pain and discomfort, bloating, and constipation experienced significant global relief (i.e., improvement in overall well-being, abdominal pain, and bowel habit) compared with placebo. Improvement in bowel movement frequency and consistency was achieved and pain was relieved by 1 week. During 12 weeks of treatment, alosetron was shown to elicit significant relief of abdominal pain and discomfort compared with placebo or mebeverine in female IBS patients with diarrhea. Alosetron slowed colonic transit and treatment efficacy was apparent after a week of treatment. Another 5-HT4 receptor agonist, prucalopride, which is being developed for chronic constipation, accelerates colonic transit and increases stool frequency. Therefore, this agent may be of benefit in IBS patients with constipation.

Topics: Abdominal Pain; Benzofurans; Clinical Trials as Topic; Colonic Diseases, Functional; Constipation; Gastrointestinal Motility; Humans; Indoles; Serotonin; Serotonin Antagonists; Serotonin Receptor Agonists; United States

Irritable bowel syndrome (IBS) is common and can be disabling. Several drugs that modulate serotonin (5HT) and other neurotransmitters in the gut (neuroenteric modulators) have either become available or are in development, but progress has been slowed by toxicity. Blockade of 5HT(3) receptors slows colonic transit, increases fluid absorption and increases left colon compliance. Alosetron, a potent 5HT(3) receptor antagonist, has, in women but not in men, a clinically significant but modest therapeutic gain over placebo in the relief of abdominal pain and discomfort and bowel-habit disturbance (but not bloating) in diarrhoea-predominant IBS. However, the drug unexpectedly was associated with ischaemic colitis and, very rarely, severe constipation-induced complications, and alosetron has been withdrawn. Cilansetron may have similar efficacy in men and women. 5HT(4) receptor stimulation results in accelerated colonic transit, and tegaserod, a partial 5HT(4) receptor agonist, has modest but clinically significant advantage over placebo in constipation-predominant IBS; the benefit seems to be confined to females. Long-term published data are lacking and safety concerns have been raised. Prucalopride, a full 5HT(4) agonist that has been promising in idiopathic chronic constipation, may also be limited by toxicity. Other 5HT receptor antagonists and agonists are under development for IBS. However, for modulators of single receptors to achieve a substantial therapeutic gain, and to do so safely, drug targets based on the pathophysiology of IBS need to be better defined.

Topics: Benzofurans; Carbolines; Clinical Trials as Topic; Colonic Diseases, Functional; Female; Humans; Indoles; Male; Serotonin Antagonists; Serotonin Receptor Agonists

Topics: Animals; Benzimidazoles; Benzofurans; Bile Acids and Salts; Carbolines; Colesevelam Hydrochloride; Colestipol; Disease Models, Animal; Enteric Nervous System; Female; Humans; Imidazoles; Indoles; Irritable Bowel Syndrome; Loperamide; Lubiprostone; Male; Mice; Natriuretic Peptides; Peptides; Phenylalanine; Receptors, Serotonin, 5-HT3; Receptors, Serotonin, 5-HT4; Rifamycins; Rifaximin; Serotonin; Serotonin Antagonists; Serotonin Receptor Agonists; Visceral Pain

Postoperative ileus (POI) is an impairment of coordinated gastrointestinal (GI) motility that develops as a consequence of abdominal surgery and is a major factor contributing to patient morbidity and prolonged hospitalization. The aim of this study was to investigate the effects of different 5-hydroxytryptamine 4 (5-HT₄) receptor agonists, which stimulate excitatory pathways, on a POI model.. The experimental model of POI in guinea pigs was created by laparotomy, gentle manipulation of the cecum for 60 seconds, and closure by suture, all under anesthesia. Different degrees of restoration of GI transit were measured by the migration of charcoal. Colonic transit was indirectly assessed via measurement of fecal pellet output every hour for 5 hours after administration of various doses of mosapride, tegaserod, prucalopride, and 5-HT.. Charcoal transit assay showed that various 5-HT₄ receptor agonists can accelerate delayed upper GI transit in a dose-dependent manner. However, fecal pellet output assay suggested that only prucalopride had a significant effect in accelerating colonic motility in POI.. Although mosapride, tegaserod, and prucalopride produce beneficial effects to hasten upper GI transit in the POI model, prucalopride administered orally restores lower GI transit as well as upper GI transit after operation in a conscious guinea pig. This drug may serve as a useful candidate for examination in a clinical trial for POI.

Topics: Administration, Oral; Animals; Benzamides; Benzofurans; Charcoal; Colon; Dose-Response Relationship, Drug; Gastrointestinal Motility; Guinea Pigs; Ileus; Indoles; Laparotomy; Male; Morpholines; Postoperative Complications; Serotonin; Serotonin 5-HT4 Receptor Agonists

Besides acting as gastrointestinal prokinetic agents, 5-hydroxytryptamine(4) (5-HT(4)) receptor agonists can induce positive inotropism in human isolated atrium, but not in ventricles. We pharmacologically evaluated the gastroprokinetic 5-HT(4) receptor agonists tegaserod, prucalopride, R199715, cisapride, the cisapride metabolite norcisapride, and the 5-HT(3) receptor agonist MKC773 on human isolated myocardial trabeculae, and compared their effects with those induced by 5-HT and 5-methoxytryptamine (5-MeOT).. Atrial and ventricular trabeculae were paced and changes in contractile force were studied in the absence or presence of the 5-HT(4) receptor antagonist GR113808. Partial agonism was assessed using 5-HT(4) receptor agonists as antagonists against 5-HT. To test the contribution of L-type calcium channels, the inotropic responses to 5-HT and 5-MeOT were studied in the absence or presence of verapamil.. Like 5-HT and 5-MeOT, cisapride and tegaserod, but not prucalopride, R19971 and MKC-733, induced concentration-dependent positive inotropic responses on atrial trabeculae, which were abolished by GR113808. The L-type calcium channel blocker verapamil attenuated inotropic responses to 5-HT and 5-MeOT. None of the agonists affected the contraction of left ventricular trabeculae. Concentration response curves to 5-HT were shifted to the right in the presence of prucalopride, cisapride, tegaserod and R199715, but not MKC-773.. We conclude that (i) inotropic responses to 5-HT and 5-MeOT seem to depend on L-type calcium channels, (ii) tegaserod and cisapride behave as partial 5-HT(4) receptor agonists, while prucalopride, norcisapride and MKC-733 cause no significant effects on human atrial trabeculae, (iii) R199715 seems to behave as a 5-HT(4) receptor antagonist.

Topics: 5-Methoxytryptamine; Adolescent; Adult; Aged; Benzofurans; Calcium Channels; Child; Cisapride; Female; Gastrointestinal Agents; Heart Atria; Heart Ventricles; Humans; Indoles; Male; Middle Aged; Muscle Contraction; Myocardium; Pyridines; Quinuclidines; Receptors, Serotonin, 5-HT4; Serotonin; Serotonin 5-HT4 Receptor Agonists; Serotonin Antagonists; Sulfonamides; Young Adult

This study examined whether the drug-receptor-binding sites of 5 selected human 5-HT(4) receptor splice variants [h5-HT4(a), h5-HT4(b), h5-HT4(c), h5-HT4(d) and h5-HT4(g)] display preferential affinities towards agonists. The agonists selected on the basis of chemical diversity and clinical relevance were: 5-HT4 benzamides, renzapride, zacopride and prucalopride; the benzimidazolones, DAU 6236 and BIMU 1; the aromatic ketone, RS67333, and the indole carbazimidamide tegaserod. The rank order of affinities ranging across the splice variants was: tegaserod (pKi: 7.38-7.91) > or = Y-36912 (pKi: 7.03-7.85) = BIMU 1 (pKi: 6.92-7.78) > or = DAU 6236 (pKi: 6.79-7.99) > or = 5-HT (pKi: 5.82-7.29) > or = 5-MeOT (pKi: 5.64-6.83) > or = renzapride (pKi: 4.85-5.56). We obtained affinity values for the 5-HT4(b), (d) and (g) variants for RS67333 (pKi: 7:48-8.29), prucalopride (pKi: 6.86-7.37) and zacopride (pKi: 5.88-7.0). These results indicate that the ligands interact with the same conserved site in each splice variant. Some splice variants have a higher affinity for certain agonists and the direction of selectivity followed a common trend of lowest affinity at the (d) variant. However, this trend was not evident in functional experiments. Our findings suggest that it may be possible to design splice variant selective ligands, which may be of relevance for experimental drugs but may be difficult to develop clinically.

Topics: Aniline Compounds; Animals; Benzamides; Benzimidazoles; Benzofurans; Binding Sites; Binding, Competitive; Bridged Bicyclo Compounds, Heterocyclic; Chlorocebus aethiops; COS Cells; Cyclic AMP; Dose-Response Relationship, Drug; Humans; Indoles; Kinetics; Ligands; Piperidines; Protein Isoforms; Receptors, Serotonin, 5-HT4; Serotonin 5-HT4 Receptor Agonists; Serotonin Antagonists

1.--In this study, we aimed to characterize in vitro the effects of the benzofuran 5-HT(4) receptor agonists prucalopride, R149402 and R199715 and the indolic agents tegaserod and 5-HT in the atria of young pigs (10-11 weeks) and newborn piglets. 2.--In the paced left atrium of young pigs, only 5-HT results in positive inotropic responses when administered cumulatively (maximal effect relative to isoprenaline=53%, pEC(50)=6.8); however, all agonists showed lusitropic effects. Noncumulative administration results in greater positive inotropic responses for 5-HT and induces moderate positive inotropic responses for the other agonists; these responses fade. 3.--Phosphodiesterase (PDE) enzyme inhibition with 3-isobutyl-1-methylxanthine (IBMX; 20 microM) enhances the responses to cumulatively administered 5-HT (maximal effect=89%, pEC(50)=7.7) and reveals clear positive inotropic effects for prucalopride, tegaserod, R149402 and R199715; fading is abolished. The maximal effect of the benzofurans is less pronounced than that of the indoles. 4.--In the spontaneously beating right atrium of young pigs, all agonists show chronotropic activity when administered cumulatively in the absence of IBMX, without fade. Benzofurans behaved as partial agonists compared to 5-HT (maximal effect=54%, pEC(50)=6.5). 5.--In newborns, the inotropic activity of the agonists in the IBMX-treated left atrium was less pronounced than in the young pig; the same applied for the chronotropic response in the right atrium, except for 5-HT. 6.--In conclusion, the atrial responses to 5-HT(4) receptor activation increase in the first months of life; the inotropic response is regulated by PDEs. Prucalopride, R149402 and R199715 are partial agonists compared to 5-HT.

Topics: Animals; Animals, Newborn; Benzamides; Benzofurans; Heart Atria; Heart Rate; In Vitro Techniques; Indoles; Myocardial Contraction; Myocardium; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases; Receptors, Serotonin, 5-HT4; Serotonin; Serotonin 5-HT4 Receptor Agonists; Sinoatrial Node; Stimulation, Chemical; Swine

Previous studies have demonstrated mixed inhibitory and facilitatory effects of 5-hydroxytryptamine-4 (5-HT(4)) receptor agonists on electrical field stimulation (EFS)-induced responses in human isolated colon. Here we report three types of responses to EFS in human isolated colon circular muscle: monophasic cholinergic contraction during EFS, biphasic response (nitrergic relaxation during EFS followed by cholinergic contraction after termination of EFS) and triphasic response (cholinergic contraction followed by nitrergic relaxation during EFS and a tachykininergic contraction after EFS). The effects of two 5-HT(4) receptor agonists, prucalopride and tegaserod were then investigated on monophasic responses only. Each compound inhibited contractions during EFS in a concentration-dependent manner. In the presence of N(omega)-nitro-l-arginine methyl ester (l-NAME) however, prucalopride and tegaserod enhanced the contractions in a concentration-dependent manner. In strips where the tone was elevated with substance-P and treated with scopolamine, EFS-induced relaxations were enhanced by the two agonists. The above observed effects by the two agonists were abolished by 5-HT(4) receptor antagonist SB-204070. The two agonists did not alter the tone raised by substance-P in the presence of scopolamine and l-NAME and did not affect carbachol-induced contractions in the presence of tetrodotoxin. These results suggest that in the circular muscle of human colon, 5-HT(4) receptor agonists simultaneously facilitate the activity of neurones which release the inhibitory and excitatory neurotransmitters, nitric oxide and acetylcholine respectively.

Topics: Acetylcholine; Adult; Aged; Aged, 80 and over; Benzofurans; Colon; Dose-Response Relationship, Drug; Electric Stimulation; Enzyme Inhibitors; Female; Humans; Indoles; Male; Middle Aged; Muscarinic Antagonists; Muscle Contraction; Muscle Relaxation; Muscle, Smooth; Neurokinin-1 Receptor Antagonists; Neurotransmitter Agents; NG-Nitroarginine Methyl Ester; Nitric Oxide; Organ Culture Techniques; Receptors, Neurokinin-2; Receptors, Neurokinin-3; Scopolamine; Serotonin 5-HT4 Receptor Agonists; Substance P

Topics: Benzofurans; Carbolines; Colonic Diseases, Functional; Female; Gastrointestinal Agents; Guanidines; Humans; Indoles; Male; Serotonin Antagonists