The alkaloid L-(-)-scopolamine [L-(-)-hyoscine], a belladonna alkaloid, competitively inhibits muscarinic receptors for acetylcholine and acts as a nonselective muscarinic antagonist, producing both peripheral antimuscarinic properties and central sedative, antiemetic, and amnestic effects. Scopolamine acts: i) as a competitive inhibitor at postganglionic muscarinic receptor sites of the parasympathetic nervous system, and ii) on smooth muscles that respond to acetylcholine but lack cholinergic innervation. It has been suggested that scopolamine acts in the central nervous system (CNS) by blocking cholinergic transmission from the vestibular nuclei to higher centers in the CNS and from the reticular formation to the vomiting center. Scopolamine can inhibit the secretion of saliva and sweat, decrease gastrointestinal secretions and motility, cause drowsiness, dilate the pupils, increase heart rate, and depress motor function. Scopolamine is used for premedication in anesthesia and for the prevention of nausea and vomiting (post operative and associated with motion sickness).

Cyclizine (cyclizine hydrochloride, Valoid®) is a histamine H1 antagonist of the piperazine class which is characterised by a low incidence of drowsiness. It possesses anticholinergic and antiemetic properties. The exact mechanism by which cyclizin (cyclizine hydrochloride, Valoid®) can prevent or suppress both nausea and vomiting from various causes is unknown. It increases lower oesophageal sphincter tone and reduces the sensitivity of the labyrinthine apparatus. It may inhibit the part of the midbrain known collectively as the emetic centre.

Cyclizine (cyclizine hydrochloride, Valoid®) is a histamine H1 antagonist of the piperazine class which is characterised by a low incidence of drowsiness. It possesses anticholinergic and antiemetic properties. The exact mechanism by which cyclizin (cyclizine hydrochloride, Valoid®) can prevent or suppress both nausea and vomiting from various causes is unknown. It increases lower oesophageal sphincter tone and reduces the sensitivity of the labyrinthine apparatus. It may inhibit the part of the midbrain known collectively as the emetic centre.

Cyclizine (cyclizine hydrochloride, Valoid®) is a histamine H1 antagonist of the piperazine class which is characterised by a low incidence of drowsiness. It possesses anticholinergic and antiemetic properties. The exact mechanism by which cyclizin (cyclizine hydrochloride, Valoid®) can prevent or suppress both nausea and vomiting from various causes is unknown. It increases lower oesophageal sphincter tone and reduces the sensitivity of the labyrinthine apparatus. It may inhibit the part of the midbrain known collectively as the emetic centre.

Dolasetron is an antinauseant and antiemetic agent, which is approved as a mesylate salt under the brand name anzement for the prevention of nausea and vomiting associated with moderately emetogenic cancer chemotherapy, including initial and repeat courses; and for the prevention of postoperative nausea and vomiting. Dolasetron is a highly specific and selective serotonin 5-HT3 receptor antagonist. The serotonin 5-HT3 receptors are located on the nerve terminals of the vagus in the periphery and centrally in the chemoreceptor trigger zone of the area postrema. It is thought that chemotherapeutic agents produce nausea and vomiting by releasing serotonin from the enterochromaffin cells of the small intestine, and that the released serotonin then activates 5-HT3 receptors located on vagal efferents to initiate the vomiting reflex. This drug is not shown to have activity at other known serotonin receptors, and has low affinity for dopamine receptors. Dolasetron mesilate is rapidly reduced by carbonyl reductase to form its major pharmacologically active metabolite reduced dolasetron. In addition dolasetron was in the phase III clinical trials for the investigation, that intravenous using of dolasetron mesilate reduces pain intensity in patients with fibromyalgia.

Dolasetron is an antinauseant and antiemetic agent, which is approved as a mesylate salt under the brand name anzement for the prevention of nausea and vomiting associated with moderately emetogenic cancer chemotherapy, including initial and repeat courses; and for the prevention of postoperative nausea and vomiting. Dolasetron is a highly specific and selective serotonin 5-HT3 receptor antagonist. The serotonin 5-HT3 receptors are located on the nerve terminals of the vagus in the periphery and centrally in the chemoreceptor trigger zone of the area postrema. It is thought that chemotherapeutic agents produce nausea and vomiting by releasing serotonin from the enterochromaffin cells of the small intestine, and that the released serotonin then activates 5-HT3 receptors located on vagal efferents to initiate the vomiting reflex. This drug is not shown to have activity at other known serotonin receptors, and has low affinity for dopamine receptors. Dolasetron mesilate is rapidly reduced by carbonyl reductase to form its major pharmacologically active metabolite reduced dolasetron. In addition dolasetron was in the phase III clinical trials for the investigation, that intravenous using of dolasetron mesilate reduces pain intensity in patients with fibromyalgia.

Dolasetron is an antinauseant and antiemetic agent, which is approved as a mesylate salt under the brand name anzement for the prevention of nausea and vomiting associated with moderately emetogenic cancer chemotherapy, including initial and repeat courses; and for the prevention of postoperative nausea and vomiting. Dolasetron is a highly specific and selective serotonin 5-HT3 receptor antagonist. The serotonin 5-HT3 receptors are located on the nerve terminals of the vagus in the periphery and centrally in the chemoreceptor trigger zone of the area postrema. It is thought that chemotherapeutic agents produce nausea and vomiting by releasing serotonin from the enterochromaffin cells of the small intestine, and that the released serotonin then activates 5-HT3 receptors located on vagal efferents to initiate the vomiting reflex. This drug is not shown to have activity at other known serotonin receptors, and has low affinity for dopamine receptors. Dolasetron mesilate is rapidly reduced by carbonyl reductase to form its major pharmacologically active metabolite reduced dolasetron. In addition dolasetron was in the phase III clinical trials for the investigation, that intravenous using of dolasetron mesilate reduces pain intensity in patients with fibromyalgia.

Tropisetron (Tropisetron-AFT) is a potent and selective serotonin 3 (5-hydroxytryptamine3; 5-HT3) receptor antagonist with antiemetic properties, probably mediated via antagonism of receptors both at peripheral sites and in the central nervous system. Surgery and treatment with certain substances, including some chemotherapeutic agents, may trigger the release of serotonin from enterochromaffin-like cells in the visceral mucosa and initiate the emesis reflex and its accompanying feeling of nausea. Tropisetron (Tropisetron-AFT) selectively blocks the excitation of the presynaptic 5-HT3 receptors of the peripheral neurons in this reflex, and may exert additional direct actions within the CNS on 5-HT3 receptors mediating the actions of vagal input to the area postrema.

Tropisetron (Tropisetron-AFT) is a potent and selective serotonin 3 (5-hydroxytryptamine3; 5-HT3) receptor antagonist with antiemetic properties, probably mediated via antagonism of receptors both at peripheral sites and in the central nervous system. Surgery and treatment with certain substances, including some chemotherapeutic agents, may trigger the release of serotonin from enterochromaffin-like cells in the visceral mucosa and initiate the emesis reflex and its accompanying feeling of nausea. Tropisetron (Tropisetron-AFT) selectively blocks the excitation of the presynaptic 5-HT3 receptors of the peripheral neurons in this reflex, and may exert additional direct actions within the CNS on 5-HT3 receptors mediating the actions of vagal input to the area postrema.

Casopitant (GW679769) is a novel substituted piperidine derivative that competitively binds with NK1 receptors. The full occupancy of the receptor by their piperidine compound inhibits its binding with tachykinin neurotransmitters, including SP. Casopitant, in a series of in vitro and in vivo experimentations, has exhibited a potent NK1 receptor antagonism. On 29 May 2008, GlaxoSmithKline announced the submission of a new drug application to the FDA for intravenous and oral formulations of casopitant mesylate. This drug was proposed for the prevention of chemotherapy-induced nausea and vomiting as an add-on therapy to the standard dual therapy of 5-HT3 receptor antagonists + dexamethasone. The submission also included a proposed indication for postoperative nausea and vomiting prevention. Rezonic™ is the proposed trade name for casopitant mesylate in the United States; Zunrisa™ is the proposed trade name for casopitant mesylate for GlaxoSmithKline’s global group of companies. In September 2009, GlaxoSmithKline decided to discontinue all regulatory filings for casopitant based on an estimate of the amount of additional safety data.