Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042963 (vomiting)
 31,883 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report describes the development of novel benzamides which are orally active, highly potent, specific antagonists of 5-HT3 receptors. Described in this first report are the structure-activity relationships that led to novel structures with improved potency and selectivity. From this series of compounds, (S)-28 was identified and selected for further evaluation as a 5-HT3 receptor antagonist. Compared with 5-HT3 antagonists such as GR 38032F, BRL 43694, and metoclopramide, (S)-28 was most active in (a) inhibiting binding to 5-HT3 receptor binding sites in rat entorhinal cortex with an Ki value of 0.19 nM and (b) blocking cisplatin-induced emesis in the ferret with an ED50 value determined to be 9 micrograms/kg po.
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PMID:Development of high-affinity 5-HT3 receptor antagonists. 1. Initial structure-activity relationship of novel benzamides. 131 2

Two randomised single-blind comparative studies were carried out in patients receiving 5-day fractionated chemotherapy. The first which has been reported previously [1] compared granisetron (40 micrograms/kg) (n = 103) with alizapride (12 mg/kg) plus dexamethasone (8 mg) (n = 94) while the second compared granisetron (40 micrograms/kg) (n = 143) with metoclopramide (7 mg/kg) plus dexamethasone (12 mg) (n = 141). Granisetron, unlike alizapride or metoclopramide is a specific 5-HT3 antagonist. The percentage of complete responders (patients with no vomiting and no worse than mild nausea) over the 5-day treatment period was higher for granisetron than for alizapride/dexamethasone (54% vs. 42.7%) (P = 0.121) or for metoclopramide/dexamethasone (46.8% vs. 43.9%). The percentage of complete responders in the first 24 h was significantly higher for granisetron (90.3%) than for alizapride/dexamethasone (65.9%) (P less than 0.001) or for metoclopramide/dexamethasone (87.4% vs. 67.9% P less than 0.0001). Granisetron was also superior to both comparators in terms of the time to the first episode of moderate/severe nausea and to less than a complete response. Significantly fewer granisetron patients were withdrawn than in the alizapride/dexamethasone group (P = 0.017) or the metoclopramide/dexamethasone group (P less than 0.0001). In both studies more comparator patients were withdrawn due to lack of efficacy and adverse events. Significantly fewer granisetron patients experienced adverse events than in either the alizapride/dexamethasone group (47.6% vs. 61.7%, P = 0.047) or the metoclopramide/dexamethasone group (60.8% vs. 77.3% P = 0.003). Granisetron patients experienced a significantly higher occurrence of constipation in both studies (10.7% vs. 3.2% and 12.6% vs. 2.8%). Headache and fever were also more frequent in the granisetron group, while extrapyramidal effects, reported by 5.3% of the alizapride/dexamethsone group and 20.6% of the metoclopramide/dexamethasone group, were not reported in any granisetron patients.
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PMID:Fractionated chemotherapy--granisetron or conventional antiemetics? The Granisetron Study Group. 132 Sep 16

The excitatory amino acid (EAA) receptor antagonists, 2,3-dihydroxy-6-nitro-7-sulphamoylbenzo(f)quinoxaline (NBQX) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), which preferentially block non-N-methyl-D-aspartate (non-NMDA) subtypes of EAA receptors, effectively inhibit cisplatin-induced emesis in ferrets. A high dose of cisplatin (10 mg/kg i.v.) was used which induced emesis in all saline-treated control ferrets. At 10 mg/kg i.v., NBQX totally prevented cisplatin-induced emesis in 5 of 6 ferrets and CNQX totally prevented emesis in 3 of 5 ferrets. By comparison, each of the 5-HT3 inhibitors, zacopride and ondansetron, at 1.0 mg/kg i.v. (a dose considered in the high therapeutic range for controlling emesis by these compounds), totally prevented emesis in 2 of 5 ferrets. It is concluded that non-NMDA antagonists effectively inhibit cisplatin-induced emesis. They are potential antiemetic compounds, alone or in combination with 5-HT3 antagonists or other more conventional drugs of choice.
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PMID:Inhibition of cisplatin-induced emesis in ferrets by the non-NMDA receptor antagonists NBQX and CNQX. 135 77

The availability of radiolabelled ligands selective for various putative neurotransmitter receptor sites and the development of quantitative autoradiography has led to a greater understanding of the neuronal pathway and receptor subtypes involved in the vomiting reflex induced by various mechanisms both within the central nervous system and the periphery. Receptors for acetylcholine, dopamine, histamine and serotonin have been detected in a number of brain regions associated with the vomiting reflex, and provide a rational basis for the antiemetic action of drugs that inhibit receptor subtypes for these neurotransmitters. The basis of the antiemetic action of other drugs such as dexamethasone and the cannabinoids is still obscure. Some drugs act on more than 1 receptor subtype. Metoclopramide may inhibit both dopamine D2- and 5-HT3 receptors in producing its antiemetic effect. Both metoclopramide and domperidone appear to have additional peripheral actions that contribute to their effectiveness. The cannabinoids are effective in cytotoxic-induced vomiting, perhaps acting via endorphin receptors or by inhibiting prostaglandin synthesis. The effectiveness of 5-HT3 receptor antagonists may depend on the block of both central and peripheral neuronal 5-HT3 receptors. Vomiting constitutes a major disadvantage to the use of many drugs; vomiting induced by aminoglycoside antibiotics appears to be due to ototoxicity and is relieved by histamine H1-receptor antagonists. The protracted vomiting associated with the use of some cytotoxics in cancer chemotherapy may involve psychic components, the chemoreceptor trigger zone and peripheral sensory neurons. Both 5-HT3 and dopamine D2-receptor antagonists exert some control, the former being more effective with cytotoxics of high emetogenic potential, such as cisplatin. Serotonin 5-HT3 receptor antagonists or high doses of metoclopramide in combination with anxiolytics and steroids as well as greater attention to pharmacokinetic profiles of the drugs involved would appear to offer improved control. The use of dopamine receptor antagonists in controlling emesis induced by dopamine agonists used in Parkinson's disease poses theoretical problems which can be overcome by using drugs with selectivity for the chemoreceptor trigger zone, such as domperidone or metoclopramide. However, higher doses of these drugs may produce some impairment of therapeutic responses to the agonists. Muscarinic and nicotinic agonists currently under investigation in Alzheimer's disease pose another therapeutic dilemma as emesis is due to a central action of these compounds. Several sites may be involved including the chemoreceptor trigger zone and frontal lobes. Opiates may act through dopamine receptors or mu-receptors on dopaminergic nerves, but serotonergic mechanisms may also be involved in the action of some opiates.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Pharmacological agents affecting emesis. A review (Part I). 137 16

Part I of this article reviewed the pathophysiology of emesis, and its pharmacological treatment. Drug-induced vomiting was also discussed. In the second part of the review, other common causes of vomiting are considered. The basis of the use of antiemetics in morning sickness and migraine is still obscure; for the latter, serotonin 5-HT1 receptor agonists, 5-HT3 receptor antagonists and dopamine D2 receptor antagonists are effective. For motion sickness, control can be achieved with various antagonists of muscarinic or histamine H1-receptors. Centrally active adrenoceptor agonists in combination with a muscarinic antagonist or H1-receptor antagonist may offer better control of motion sickness and its associated symptoms than either antagonist alone; based on clinical studies, postoperative vomiting after opiate administration appears to be controlled by blocking dopamine D2, histamine H1- or muscarinic receptors. Radiation therapy appears to be similar to cytotoxic therapy in that the mediators produced or released by radiation activate both peripheral and central sites involved in the vomiting reflex. Blockade of dopamine D2 and 5-HT3 receptors may be effective.
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PMID:Pharmacological agents affecting emesis. A review (Part II). 137 13

Oral tropisetron, a 5-hydroxytryptamine type 3 (serotonin3) [5-HT3]-receptor antagonist, at a dose of 5mg daily was evaluated as antiemetic prophylaxis during postoperative abdominal irradiation. 20 women with International Federation of Gynecology and Obstetrics (FIGO) stage I to III ovarian carcinoma were included. 12 women received irradiation of whole abdominal fields and 8 of lower abdominal/pelvic fields. Efficacy and adverse events were recorded by the patients in diary-form booklets. The cumulative weekly incidence of patients with nausea, which was generally mild and of short duration, increased from 30% at the start of radiotherapy to 54% at the end of treatment. Episodes of vomiting occurred in less than 10% of the patients. Diarrhoea was common towards the end of the radiotherapy courses, and the proportion of patients needing extra antidiarrhoeal medication (loperamide) increased from 38% during the first week to 100% at the end of the radiotherapy course. Mean weight loss was 1.2kg during the 5- to 6-week course. Overall ratings for quality of life were excellent or good in 75 to 85% of patients. Tropisetron seems to be a promising and well tolerated drug in conjunction with extended radiotherapy of abdominal fields. This was an open study, establishing the methodology for long term follow-up of patients during fractionated radiotherapy.
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PMID:Tropisetron, a new 5-HT3-receptor antagonist, in the prevention of radiation-induced nausea, vomiting and diarrhoea. 138 Apr 31

Ondansetron is a highly selective 5-HT3 antagonist, which has recently become available for the control of chemotherapy-induced emesis. Since 5-HT3 receptors not only have a high density in the area postrema but also in the hippocampal and amygdala region of the limbic system, it has been suspected that 5-HT3 selective agents have psychotropic effects. In animal models of anxiety ondansetron showed a benzodiazepine-like anxiolytic effect without any sedation or withdrawal effects. Other states of withdrawal have been prevented with ondansetron. This agent might also exert neuroleptic effects since dopaminergic hyperactivity in the mesolimbic system was antagonised by ondansetron. In different models of memory and learning a positive effect on basal learning behaviour and on scopolamine-induced memory impairment was noted. This manuscript reviews essential pharmacological and behavioural effects of ondansetron as well as preliminary data from clinical studies. The role of highly-selective ligands for a more differentiated view of serotonergic subsystems are discussed.
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PMID:[Ondansetron--the first highly selective 5-HT3 antagonist in therapy of psychiatric diseases]. 138 89

Ondansetron (GR 38032) has potent and highly selective antagonist properties at the 5-hydroxytryptamine (5-HT, serotonin) 5-HT3 receptor. The selectivity ratio for ondansetron on 5-HT3 receptors compared with actions on other neurotransmitter receptor types is greater than 1,000. The antiemetic properties of ondansetron have been determined in ferrets against the nausea and vomiting induced by cisplatin, cyclophosphamide, and whole-body radiation. Ondansetron (intravenous 0.01 to 0.1 mg/kg or subcutaneous 0.1 to 0.5 mg/kg) or metoclopramide (1.0 to 4.0 mg/kg) cause dose-dependent inhibitions of the vomiting induced by each of these procedures. Unlike ondansetron, the effects of metoclopramide are accompanied by moderate to marked behavioral depression. Since metoclopramide is 50 times more potent on dopamine D2 receptors than on 5-HT3 receptors, the behavioral depression is likely due to profound blockade of dopamine receptors. The 5-HT3 receptors have been shown to be present peripherally on vagal afferent fibers and are densely located in the vomiting center of the hindbrain. The current hypothesis is that there may be both a peripheral and a central site of action for ondansetron and other 5-HT3 antagonists. The lack of antagonist activity on dopamine and other non-5-HT3 receptors indicates that, unlike metoclopramide, ondansetron will not cause extrapyramidal or other dose-limiting side effects.
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PMID:Pharmacology and preclinical antiemetic properties of ondansetron. 138 45

The emetogenic properties of chemotherapeutic agents differ in terms of the frequency, intensity, time of onset, and duration of vomiting and nausea. As the effects of antiemetic agents in the control of emesis induced by different chemotherapeutic agents could differ, new antiemetics must be tested against a variety of chemotherapy challenges. In many non-cisplatin chemotherapy situations, a partly or totally oral schedule of antiemetic administration may be preferable. The selective 5-hydroxytryptamine (5-HT3)-receptor antagonist, ondansetron, has been shown to be a safe, effective, and well-tolerated antiemetic in the prevention of nausea and vomiting from several non-cisplatin chemotherapies. In randomized studies, ondansetron has compared favorably with metoclopramide in patients receiving cyclophosphamide-containing chemotherapy regimens.
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PMID:Antiemetic activity of ondansetron in cancer patients receiving non-cisplatin chemotherapy. 138 49

Hepatic oxidative metabolism accounts for more than 95% of ondansetron clearance from the body. The major excreted metabolites are conjugates of 7-hydroxy or 8-hydroxyondansetron, which appear to contribute little to the activity of the parent drug. Ondansetron plasma clearance averages approximately 0.45 L/h/kg, is similar in young male volunteers and cancer patients undergoing cisplatin-based chemotherapy, and does not change significantly with repeated dosing. Clearance decreases with increasing age, whereas volume of distribution remains unchanged. The result is an increase in mean plasma half-life from 3.5 hours in young volunteers (18-40 years) to 5.5 hours in volunteers over 75 years of age. Clearance and volume of distribution are higher in young (7-12 years) cancer patients, resulting in a mean plasma half-life of 2.5 hours. Plasma clearance is slightly slower in females. Ondansetron clearance decreases and half-life increases in patients with severe hepatic insufficiency. Clearance may be enhanced in patients receiving known hepatic enzyme inducers. Because of large intersubject variability in clearance and the relative safety of ondansetron, adjustments in ondansetron dosing based on age or gender alone are not recommended. Ondansetron is rapidly and completely absorbed when administered as a tablet. A relationship exists between control of emesis and the area under the plasma concentration-time curve for ondansetron. All data collected to date support the thesis that ondansetron is a competitive antagonist of the 5-hydroxytryptamine (5-HT3) receptor in humans.
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PMID:Ondansetron metabolism and pharmacokinetics. 138 54


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