Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022104 (irritable bowel syndrome)
 8,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Functional (nonulcer) dyspepsia refers to upper abdominal pain or discomfort with or without symptoms of early satiety, nausea, or vomiting with no definable organic cause. The current Rome II criteria help to diagnose functional dyspepsia and avoid misdiagnosis of gastroesophageal reflux disease and irritable bowel syndrome as functional dyspepsia. Assessment of gastric emptying with scintigraphy or breath testing may be useful in identifying delayed gastric emptying in patients with dyspeptic symptoms and may be helpful in patient management. Electrogastrography is a noninvasive test that evaluates for gastric dysrhythmias. Satiety testing is being evaluated as an indirect test for impaired fundic relaxation and visceral hypersensitivity. The symptom response to Helicobacter pylori therapy in patients with functional dyspepsia and a negative endoscopy examination but a positive H. pylori test is marginal. Lifestyle modifications often are suggested for initial treatment of functional dyspepsia. Dietary changes such as frequent small meals, low-fat diet, and avoidance of certain aggravating foods may improve symptoms. Additional measures include cessation of smoking, avoiding excess alcohol intake, and minimizing coffee intake. Antacids and over-the-counter histamine type 2 receptor antagonists may be helpful as an "on-demand" therapy for intermittent symptoms. They are safe and relatively inexpensive. Different subgroups of functional dyspepsia are based on the predominant symptom and may help in choosing an appropriate drug to initiate therapy. If the predominant symptom is epigastric pain (ulcer-like functional dyspepsia), histamine-2 receptor antagonists or proton pump inhibitors are the initial treatment of choice. If fullness, bloating, early satiety or nausea is the predominant complaint (dysmotility-like functional dyspepsia), a prokinetic agent may help. Metoclopramide is the only available effective prokinetic agent at present. If metoclopramide is used, short-term treatment and discussion of possible side effects with the patient are advised. If there is no response to these initial treatments, switching therapy from proton pump inhibitor to prokinetic or vice versa can be tried. If these treatment options fail, patient re-evaluation for other disorders (including other functional bowel disorders) is advised. A low-dose tricyclic antidepressant at bedtime may be helpful for treatment of visceral hypersensitivity.
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PMID:Functional (Nonulcer) Dyspepsia. 1187 96

Pfizer is developing ezlopitant, a neurokinin-1 antagonist, for the potential treatment of irritable bowel syndrome (IBS). The compound had undergone phase II trials in the US and Europe, and phase I in Japan for treatment of chemotherapy-induced emesis [290988], [320737], [329187]. A phase II, double-blind, randomized study was performed to assess the safety and efficacy of ezlopitant for the control of cisplatin-induced emesis. Treatment was well tolerated [290988]. Although the compound effectively controls emesis, it is less effective in controlling nausea, and development has been discontinued for the emesis indication [347367]. Ezlopitant has undergone a pilot study in 14 IBS patients [367631].
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PMID:Eziopitant. Pfizer. 1189 Mar 62

Symptoms associated with Dientamoeba fragilis include diarrhoea, abdominal pain, nausea, vomiting, epigastric pain and weight loss. A possible link between D. fragilis and irritable bowel syndrome (IBS)-like symptoms has been reported, and therefore the presence of this parasite should be excluded before making a diagnosis of IBS. Over a six-month period, 976 faecal samples were submitted to NPHS Microbiology Aberystwyth for routine microbiological analysis. All samples were also cultured for parasites using Robinson's xenic medium. Trichrome staining was undertaken whenever practicable, but many stools had insufficient material. D. fragilis was isolated from 25 (2.6%) patients, whereas Cryptosporidium spp. was detected in 16 (1.6%) patients. D. fragilis was only detected in nine (1.3%) out of 685 specimens stained with trichrome, although four of the 25 culture-positive stools had insufficient sample for staining. Parasite culture proved to be less laborious than trichrome staining and dramatically increased D. fragilis detection rate.
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PMID:Detection of Dientamoeba fragilis by culture. 1286 14

The 5-HT3A receptor, a ligand-gated ion channel, is involved in pain pathways, nausea and emesis, and irritable bowel syndrome, and may play a role in the pathogenesis of psychiatric diseases such as schizophrenia and depression. Recently, a naturally occurring variation (ProArg) in the second intracellular loop of the human (h) 5-HT3A receptor was identified in a schizophrenic patient. Because the substitution of proline, an alpha-imino acid, by arginine may affect the conformation of the whole receptor, the aim of the present study was to determine the pharmacological and functional properties of this variant compared to the wild-type receptor in stably transfected HEK293 cells. Studies of binding of [H]GR65630, a 5-HT3 receptor antagonist, to membranes (saturation and competition experiments with 5-HT3 receptor ligands) and patch-clamp studies of agonist-induced currents in outside-out patches were carried out. In comparison to the wild-type, the variant receptor exhibited no changes in the receptor density and the affinities for nine representative ligands (five agonists and four antagonists). The potencies and efficacies of three 5-HT3 receptor agonists in inducing currents through the ion channel and the potencies of two 5-HT3 receptor antagonists in blocking 5-HT-evoked currents did not differ between wild-type and variant receptors. In addition, there were no differences in the desensitization kinetics of both receptor isoforms. In conclusion, the ArgPro variation of the h5-HT3A receptor does not change ligand binding to the h5-HT3A receptor, nor does it modify current through the receptor channel.
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PMID:Pharmacological and electrophysiological properties of the naturally occurring Pro391Arg variant of the human 5-HT3A receptor. 1516 4

This article reviews the safety and tolerability profile of tegaserod, a novel selective partial agonist of the serotonin 5-HT(4) receptor. Tegaserod was recently approved for the treatment of women with irritable bowel syndrome (IBS) with constipation. Tegaserod exhibits rapid absorption from the small intestine, and is excreted unchanged in the faeces and as metabolites in the urine. Meal ingestion decreases its bioavailability. There is little effect of age or gender on pharmacokinetics, although plasma levels may be slightly higher in the elderly. Tegaserod has no effect on plasma levels of other drugs metabolised by cytochrome P450 enzyme systems. Gastrointestinal symptoms are the most common adverse effects of tegaserod therapy. In data pooled from phase III randomised controlled trials (RCTs) in IBS with constipation patients, diarrhoea was reported by 8.8% of patients treated with tegaserod 6mg twice daily versus 3.8% of patients receiving placebo. Similar rates have been observed in international post-US marketing RCTs. In most patients, tegaserod-induced diarrhoea was mild and transient. In RCTs, it did not elicit fluid or electrolyte disturbances, and fewer than 3% of IBS patients discontinued tegaserod due to diarrhoea. Since its release, rare cases of more severe diarrhoea and ischaemic colitis have been reported. The incidence of other gastrointestinal symptoms (e.g. abdominal pain, nausea, and flatulence) has been similar among tegaserod-treated patients and placebo-treated patients. Pooled analysis of phase III RCTs and post-US marketing RCTs have not demonstrated significant differences between tegaserod-treated patients and placebo-treated patients in the incidence of abdominal-pelvic surgery. There is no convincing evidence that rebound gastrointestinal symptoms occur upon termination of tegaserod therapy. Pooled analysis of phase III RCTs demonstrated an increase in the incidence of headaches among tegaserod-treated patients (6mg twice daily) compared with placebo-treated patients (15% vs 12.3%, respectively, p < 0.05), although post-US marketing RCTs have not observed this increase. Other extra-gastrointestinal adverse events occur with similar frequency among tegaserod-treated patients and placebo-treated patients. Tegaserod-treated patients in RCTs have not demonstrated significant prolongation of the QTc interval or cardiac arrhythmias compared with placebo-treated patients. Supra-therapeutic doses in healthy volunteers did not effect electrocardiographic parameters. Laboratory parameters are mostly unaffected by tegaserod, although several individuals have exhibited increased eosinophil counts. In summary, tegaserod exhibits a favourable safety and tolerability profile in IBS patients based on data from clinical trials. Diarrhoea is the most common adverse event associated with tegaserod use. Continued post-US marketing surveillance will further define the safety and tolerability profile of tegaserod.
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PMID:Safety profile of tegaserod, a 5-HT4 receptor agonist, for the treatment of irritable bowel syndrome. 1523 Jun 44

The term 'Functional diseases' implies symptoms arising from an organ without overt pathology. However this is more apparent than real since inflammation often leaves changes in nerves and mucosal function only apparent with specialised techniques. Acute onset functional dyspepsia accounts for around 1/5 of functional dyspepsia and is characterised by early satiety, nausea, vomiting and weight loss. Impaired postcibal fundal accommodation may underlie some of these symptoms. Post infectious gastroparesis is much rarer and is associated with markedly delayed gastric emptying and antral hypomotility. Approximately 1/10 of IBS cases describe a post infectious onset. Post infectious IBS is typically of the diarrhoea-predominant type. Post inflammatory functional diseases tend to be associated with less psychological abnormalities and have a better prognosis than other functional diseases. There are isolated anecdotal reports of symptom response to anti-inflammatory treatments but larger controlled trials are needed.
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PMID:Inflammation as a basis for functional GI disorders. 1532 5

Several 5-HT3 receptor antagonists are available (tropisetron, ondansetron, granisetron, dolasetron, and palonsetron), and further compounds are in clinical development. These substances show only minor differences in the activity profile regarding their affinity for particular receptors. 5-HT3 receptor antagonists are primarily used and found effective in the prevention and treatment of chemotherapy-induced nausea and emesis, and in postoperative nausea and vomiting (PONV). Antagonism of the 5-HT3 receptors in the peripheral and central nervous system is a probable mechanism of action. The substances are suitable as first-line therapy (combined with a corticosteroid) for the prevention of acute nausea and vomiting in patients treated with moderately to severely emetogenic chemotherapeutic agents. This combination is also moderately effective in the prevention of delayed nausea and vomiting. 5-HT3 receptor antagonists are an important constituent in the prevention and treatment of emesis and nausea caused by radiation therapy, especially in patients receiving whole body or upper abdominal treatment. Alosetron was found clinically effective in diarrhoea-predominant irritable bowel syndrome, whereas tropisetron in fibromyalgia and related pain disorders. Further indications for such treatment include anxiety disorders, alcohol dependence, drug withdrawal, and psychosis related to treatment of Parkinson's disease. 5-HT3 receptor antagonists are well tolerated with the most frequently reported adverse effects being headache, constipation, dizziness, tiredness, and gastrointestinal disturbances such as abdominal pain or constipation. Intravenous administration of serotonin induces the Bezold-Jarisch reflex and causes small reversible changes in electrocardiogram (ECG) parameters.
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PMID:Spectrum of use and tolerability of 5-HT3 receptor antagonists. 1551 6

Gastrointestinal symptoms are the most common side-effects of tegaserod therapy. In data pooled from Phase III randomized controlled trials in patients with irritable bowel syndrome with constipation, diarrhoea was reported by 8.8% of patients treated with tegaserod 6 mg b.d. vs. 3.8% of patients treated with placebo. Similar rates were observed in international post-US marketing randomized controlled trials. In most patients, tegaserod-induced diarrhoea was mild and transient. In randomized controlled trials, it did not elicit fluid or electrolyte disturbances, and fewer than 3% of irritable bowel syndrome patients discontinued tegaserod due to diarrhoea. The incidence of other gastrointestinal symptoms (e.g. abdominal pain, nausea and flatulence) was similar in tegaserod-treated and placebo-treated patients. Pooled analysis of Phase III and post-US marketing randomized controlled trials did not demonstrate significant differences between tegaserod-treated and placebo-treated patients in the incidence of abdominal/pelvic surgery. No episodes of ischaemic colitis were reported in tegaserod-using patients in any Phase III or post-marketing randomized controlled trials, and post-marketing surveillance indicated that the rate of ischaemic colitis in tegaserod-using patients was lower than that in non-tegaserod-using patients. Pooled analysis of Phase III randomized controlled trials demonstrated an increase in the incidence of headaches in tegaserod-treated (6 mg b.d.) vs. placebo-treated patients (15% vs. 12.3%, respectively; P < 0.05), although post-US marketing randomized controlled trials did not demonstrate this increase. Other extra-gastrointestinal adverse events occurred with similar frequency in tegaserod-treated and placebo-treated patients. Tegaserod-treated patients in randomized controlled trials did not demonstrate significant prolongation of the QTc interval or cardiac arrhythmias compared with placebo-treated patients. In summary, tegaserod exhibits a favourable safety and tolerability profile in irritable bowel syndrome patients based on data from clinical trials.
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PMID:Review article: the safety profile of tegaserod. 1552 52

Idiopathic dyspepsia refers to pain and/or discomfort perceived in the epigastrium that is not secondary to organic, systemic, or metabolic diseases. Symptoms may overlap with those of gastroesophageal reflux disease and irritable bowel syndrome. Gastrointestinal motor disorders, hypersensitivity to mechanical or chemical stimuli, and psychosocial factors can act individually or in concert to induce the symptoms of dyspepsia. Accordingly, there is no single therapy, and treatment must be individualized. Eradication of Helicobacter pylori infection rarely achieves symptom improvement. Treatment of idiopathic dyspepsia should begin by reassuring the patient about the benign nature of the syndrome and educating them on the knowledge that has been achieved in recent years regarding potential causes of the syndrome. Both prokinetic and antisecretory drugs have been reported to improve dyspeptic symptoms, but results are not completely convincing. Although well-designed studies demonstrate superiority of proton pump inhibitors over placebo, it should be noted that patients with nonerosive gastroesophageal reflux disease were invariably included; when these patients are excluded, the benefit of antisecretory medications is questionable. We suggest that patients with idiopathic dyspepsia be initially treated according to the predominant symptom. Those with epigastric pain/burning should receive a trial with standard doses of proton pump inhibitors for 4 to 8 weeks, whereas prokinetic patients should be prescribed at recommended doses for similar periods of time to patients with nonpainful dyspeptic symptoms such as posprandial fullness, early satiety, nausea, or vomiting. Nonresponders may benefit from combination therapies or short trials with higher doses of drugs. Visceral analgesics and antidepressants can also be prescribed alone or in combinations with other therapeutic strategies. Recent studies demonstrate utility for psychologic therapy and hypnotherapy, although truly controlled studies are difficult in this area. Herbal medicines deserve further evaluation.
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PMID:Idiopathic Dyspepsia. 1576 39

The bowel exhibits reflexes in the absence of CNS input. To do so, epithelial sensory transducers, such as enterochromaffin (EC) cells, activate the mucosal processes of intrinsic (IPANs) and extrinsic primary afferent (sensory) neurons. EC cells secrete serotonin (5-HT) in response to mucosal stimuli. Submucosal IPANs, which secrete acetylcholine and calcitonin gene-related peptide, initiate peristaltic and secretory reflexes and are activated via "5-HT1P" receptors. Release of neurotransmitters is enhanced by 5-HT4 receptors, which are presynaptic and strengthen neurotransmission in prokinetic pathways. 5-HT3 receptors mediate signaling to the CNS and thus ameliorate cancer chemotherapy-associated nausea and the visceral hypersensitivity of diarrhea-predominant irritable bowel syndrome (IBS-D); however, because 5-HT3 receptors also mediate fast ENS neurotransmission and activate myenteric IPANs, they may be constipating. 5-HT4 agonists are prokinetic and relieve discomfort and constipation in IBS-C and chronic constipation. 5-HT4 agonists do not initiate peristaltic and secretory reflexes but strengthen pathways that are naturally activated. Serotonergic signaling in the mucosa and the ENS is terminated by a transmembrane 5-HT transporter, SERT. Mucosal SERT and tryptophan hydroxylase-1 expression are decreased in experimental inflammation, IBS-C, IBS-D, and ulcerative colitis. Potentiation of 5-HT due to the SERT decrease could account for the discomfort and diarrhea of IBS-D, while receptor desensitization may cause constipation. Similar symptoms are seen in transgenic mice that lack SERT. The loss of mucosal SERT may thus contribute to IBS pathogenesis.
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PMID:Nerves, reflexes, and the enteric nervous system: pathogenesis of the irritable bowel syndrome. 1579 84


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