Emistat

Anset is a serotonin subtype 3 (5-HT3) receptor antagonist indicated:
Prevention of nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy.
Prevention and treatment of post-operative nausea and vomiting.
Prevention of radiotherapy-induced nausea and vomiting.

Frequently reported adverse events were headache, constipation and diarrhea, but the majority have been mild or moderate in nature. In chemotherapy-induced nausea and vomiting, rash has occurred in approximately 1% of patients receiving Anset. There also have been reports to a sensation of flushing or warmth, hiccups and liver enzyme abnormalities. Rare cases of anaphylaxis, brochospasm, tachycardia, angina (chest pain), hypokalemia, shortness of breath have also been reported, except for bronchospasm and anaphylaxis, the relationship to Anset is unclear. There have been no evidence to extrapyramidal reactions, in rare case oculogyric crisis appearing alone, as well as with other dystonic reactions without definitive clinical evidence. In case of PONV, with the exception of headache, rates of these events were not significantly different in the Anset and placebo groups.

Hypersensitivity reactions have been reported in patients who have exhibited hypersensitivity to other selective 5-HT3 receptor antagonists. Anset is not a drug that stimulates gastric or intestinal peristalsis. It should not be used instead of nasogastric suction. The use of Anset in patients following abdominal surgery or in patients with chemotherapy-induced nausea and vomiting may mask a progressive ileus and/or gastric distension.

Ondansetron is a potent, highly selective 5HT
3
receptor-antagonist. Its precise mode of action in the control of nausea and vomiting is not known. Chemotherapeutic agents and radiotherapy may cause release of 5HT in the small intestine initiating a vomiting reflex by activating vagal afferents via 5HT
3
receptors. Ondansetron blocks the initiation of this reflex. Activation of vagal afferents may also cause a release of 5HT in the area postrema, located on the floor of the fourth ventricle, and this may also promote emesis through a central mechanism. Thus, the effect of ondansetron in the management of the nausea and vomiting induced by cytotoxic chemotherapy and radiotherapy is probably due to antagonism of 5HT
3
receptors on neurons located both in the peripheral and central nervous system. The mechanisms of action in post-operative nausea and vomiting are not known but there may be common pathways with cytotoxic induced nausea and vomiting.