Showing papers on "Granisetron published in 1990"

The effects of granisetron, ICS 205–930 and ondansetron on the visceral pain reflex induced by duodenal distension

Abstract: 1. Distension of the duodenum in anaesthetized rats, by rapid application of intraluminal pressures (10-75 cmH2O), evoked falls in diastolic blood pressure and intragastric pressure. 2. The distension-induced responses were blocked by pretreatment with morphine (20 mg kg-1, s.c.), an action reversible by injection of naloxone (5 mg kg-1, i.v.). 3. Bilateral cervical vagotomy reduced the distension-evoked fall in intragastric pressure but had no effect on the corresponding fall in blood pressure. 4. Granisetron or ICS 205-930 (1-1000 micrograms kg-1, i.v.) had no effects on duodenal intraluminal pressure, but reduced the responses to distension with a bell-shaped dose-response relationship. Ondansetron (1-1000 micrograms kg-1, i.v.) did not reduce the reflex responses. 5. These results show that the 5-HT3 receptor antagonists used exerted different effects on the reflex responses to duodenal distension.

Phase I/II trial of granisetron: a novel 5-hydroxytryptamine antagonist for the prevention of chemotherapy-induced nausea and vomiting.

Abstract: A new class of antiemetic agents, the 5-hydroxytryptamine (5-HT3) antagonists, have been shown to possess potent antiemetic properties in the ferret model. We conducted a phase I/II trial of the 5-HT3 antagonist BRL43694 (granisetron) in 24 chemotherapy-naive patients who were receiving any combination of doxorubicin and/or cisplatin. The first 12 patients received 40 micrograms/kg and the second 12 received 80 micrograms/kg of granisetron intravenously before beginning chemotherapy. Nausea was assessed by a patient-completed visual analogue scale and episodes of retching recorded by the patient and an independent observer. Fifty-two percent of the 22 evaluable patients had no retching or vomiting and 32% had no nausea during the first 24 hours after chemotherapy. Pharmacokinetic measurements were performed. The disposition of granisetron was best described using a two-compartment model. The area under the plasma concentration curve (AUC) was 277 +/- 226 ng.h/mL and 359 +/- 282 ng.h/mL at 40 and 80 microg...

Emesis and defecations induced by the 5-hydroxytryptamine (5-HT3) receptor antagonist zacopride in the ferret.

Abstract: Three antiemetic compounds (zacopride, batanopride, granisetron [BRL43694]) were evaluated for the production of gastrointestinal side effects in the conscious ferret after i.v. or p.o. administration. Zacopride evoked multiple emetic and defecatory responses at clinically relevant doses (0.003-0.3 mg/kg) and in a dose-dependent manner. The oral route was the more potent one for eliciting emesis (ED50 0.033 mg/kg). At 0.3 mg/kg p.o., zacopride reliably evoked an 80 to 100% incidence of emesis and a 40 to 80% incidence of defecation. In contrast, batanopride and BRL43694 i.v. evoked a small (10%) incidence of these side effects, but only at 0.1 to 10 mg/kg doses. When given p.o. (0.00003-10 mg/kg), these latter compounds never evoked emesis and significantly reduced (P less than .05) the incidence of defecation below that of vehicle. Responses to zacopride (0.3 mg/kg p.o.) were challenged by i.p. pretreatment with the 5-hydroxytryptamine receptor agonist 2-methyl serotonin, the 5-hydroxytryptamine receptor antagonist BRL43694, the quaternary atropine derivative glycopyrrolate, the dopamine receptor antagonist domperidone or selective abdominal vagotomies. All compounds and either bilateral or dorsal vagotomy significantly reduced the incidence of emesis, but did not abolish it. Latency to first emesis was delayed by BRL43694, domperidone or dorsal vagotomy. The data suggest that the emetic response to p.o. zacopride is mediated in part by 5-hydroxytryptamine receptors residing on either enteric neurons or vagal afferents. However, the underlying pharmacology of the response may also include activation of cholinergic and dopaminergic pathways.

Vagal-induced vomiting in decerebrate cat is not suppressed by specific 5-HT3 receptor antagonists.

Abstract: Cancer therapy with cytotoxic drugs such as cisplatin or cyclophosphamide is usually associated with violent crisis of vomiting. Recently, it was shown that 5-HT 3 receptor antagonists block cisplatin-induced vomiting but the mechanisms and their sites of action remain unknown. We tested the hypothesis that these agents act on structures within the central nervous system by evaluating the effectiveness of vagal stimulation in eliciting fictive vomiting in decerebrate, paralyzed and ventilated cats before and after administration of such agents. Fictive vomiting was defined as a series of large bursts of synchronous activity in the phrenic and abdominal (expiratory) nerves (retching) followed by a burst in which the abdominal activity was prolonged (expulsion). The latency and number of these co-activations were measured before and after intravenous administration of three 5-HT 3 receptor antagonists (GR 38032F (Ondansetron), Zacopride, and BRL 43694A (Granisetron)). All compounds, administered at doses of 1 and 2 mg/kg failed to block vomiting behaviour in 100% and 68% of trials, respectively. Nor did their administration affect the latency and number of co-activations. We conclude that intravenous administration of 5-HT 3 receptor antagonists do not act centrally on either the brainstem neuronal network known as the “vomiting center” or related neuronal structures. Our results suggest that the anti-emetic effect of 5-HT 3 receptor antagonists in cisplatin-induced vomiting is mediated peripherally rather than centrally.

High versus low dose granisetron, a selective 5HT3 antagonist, for the prevention of chemotherapy-induced nausea and vomiting.

Abstract: Fifty six patients, with histologically confirmed cancer, who received highly emetogenic chemotherapy, were entered on a randomized double blind, low versus high dose, study of granisetron, a 5HT3 receptor antagonist. A single dose of intravenous granisetron protected the majority of patients from nausea and vomiting, 160 μg/kg was more effective than 40 μg/kg with no more side effects. Additional doses of granisetron conferred added benefit to patients who experienced breakthrough symptoms. Granisetron at a dose range of 40–240 μg/kg over a 24 hour period was well tolerated with the only side effect being mild headache.