Tubocurarine, a naturally occurring alkaloid, is used to treat smoking withdrawl syndrom. Tubocurarine, the chief alkaloid in tobacco products, binds stereo-selectively to nicotinic-cholinergic receptors at the autonomic ganglia, in the adrenal medulla, at neuromuscular junctions, and in the brain. Two types of central nervous system effects are believed to be the basis of Tubocurarine's positively reinforcing properties. A stimulating effect is exerted mainly in the cortex via the locus ceruleus and a reward effect is exerted in the limbic system. At low doses the stimulant effects predominate while at high doses the reward effects predominate. Intermittent intravenous administration of Tubocurarine activates neurohormonal pathways, releasing acetylcholine, norepinephrine, dopamine, serotonin, vasopressin, beta-endorphin, growth hormone, and ACTH. Tubocurarine competes with acetylcholine for post-synaptic nicotinic NM receptors and blocks them.

Tubocurarine, a naturally occurring alkaloid, is used to treat smoking withdrawl syndrom. Tubocurarine, the chief alkaloid in tobacco products, binds stereo-selectively to nicotinic-cholinergic receptors at the autonomic ganglia, in the adrenal medulla, at neuromuscular junctions, and in the brain. Two types of central nervous system effects are believed to be the basis of Tubocurarine's positively reinforcing properties. A stimulating effect is exerted mainly in the cortex via the locus ceruleus and a reward effect is exerted in the limbic system. At low doses the stimulant effects predominate while at high doses the reward effects predominate. Intermittent intravenous administration of Tubocurarine activates neurohormonal pathways, releasing acetylcholine, norepinephrine, dopamine, serotonin, vasopressin, beta-endorphin, growth hormone, and ACTH. Tubocurarine competes with acetylcholine for post-synaptic nicotinic NM receptors and blocks them.

Hydrastinine is a synthetic alkaloid prepared by various processes from either hydrastine, berberine, or narcotine. It exerts a strong stimulating action on the uterus of all species studied, including human. Hydrastinine and the closely related alkaloid cotarnine have been employed as hemostatics, particularly in abnormal uterine conditions. In the non-pregnant animal, hydrastinine in doses of 10 mg. depressed both tonus and activity, even after the section of the hypogastric. In the pregnant cat, it caused the uterus to contract. A stimulant action was also noted in the non-pregnant animal if nicotine were administered prior to hydrastinine. The rabbit uterus in situ was strongly contracted. Laidlaw believed that hydrastinine acted on the uterus both directly on the smooth muscle and also through its sympathetic innervation. Repeated administration of large doses for a period of time resulted in greatly increased amplitude of contractions which persisted after removal of the drug. The drug was patented by Bayer as a haemostatic drug during the 1910s.

Domperidone is a peripherally selective D2 receptor antagonist. It acts as an antiemetic and a prokinetic agent through its effects on the chemoreceptor trigger zone and motor function of the stomach and small intestine. Domperidone was not approved in USA due to risks of cardiac arrhythmias, cardiac arrest, and sudden death, but is available in other countries. However, FDA allows access to Domperidone through an expanded access investigational new drug application (IND) to patients with gastroesophageal reflux disease with upper GI symptoms, gastroparesis, and chronic constipation. As an “off-label” use, domperidone is prescribed to breastfeeding women to enhance their milk production.

Domperidone is a peripherally selective D2 receptor antagonist. It acts as an antiemetic and a prokinetic agent through its effects on the chemoreceptor trigger zone and motor function of the stomach and small intestine. Domperidone was not approved in USA due to risks of cardiac arrhythmias, cardiac arrest, and sudden death, but is available in other countries. However, FDA allows access to Domperidone through an expanded access investigational new drug application (IND) to patients with gastroesophageal reflux disease with upper GI symptoms, gastroparesis, and chronic constipation. As an “off-label” use, domperidone is prescribed to breastfeeding women to enhance their milk production.

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.

Elobixibat is the first in class ileal bile acid transporter (IBAT) inhibitor. IBAT inhibitors block ileal absorption of bile acids by: (1) interrupting the enterohepatic circulation of bile resulting in a fall in serum cholesterol and (2) increasing the delivery of bile acids into the colon. Elobixibat stimulates both motor and secretory functions in the colon. Elobixibat is approved in Japan for the treatment of chronic constipation. Elobixibat has potential benefit in the treatment of non-alcoholic steatohepatitis.

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.

Azasetron is an antiemetic drug. It acts as serotonin 3 receptor antagonist. It is currently used to prevent nausea and vomiting caused by cancer chemotherapy (including cisplatin chemotherapy). Also it was demonstrated that azasetron has potent antimitogenic and apoptotic effect on cancer cell line. It was preclinically tested to treat cocaine abuse.

Oteracil is an adjunct to antineoplastic therapy, used in combination with Gimeracil and Tegafur. Gimeracil/oteracil/tegafur combination is approved for the gastric cancer treatment. Oteracil is an orotate phosphoribosyltransferase (OPRT) inhibitor that decreases the activity of 5-fluorocil (tegafur is a prodrug of 5-fluorocil) in normal gastrointestinal mucosa.