Chemotherapeutic agents, emetic

Numerous neurotransmitter receptors are located in the vomiting center, CTZ, and GI tract. Examples of such receptors include cholinergic and histaminic, dopaminergic, opiate, serotonin, neurokinin (NK), and benzodiazepine receptors. Theoretically, chemotherapeutic agents, their metabolites, or other emetic compounds trigger the process of emesis through stimulation of one or more of these receptors. 

Ondansetron is a 5HT3 antagonist indicated as an anti-emetic agent in nausea and vomiting associated with chemotherapy. The dose administered depends on the emetogenic degree of the chemotherapeutic agents used. 

Effective antiemetic agent for the treatment of postoperative nausea and vomiting, nausea and vomiting secondary to mildly emetic chemotherapeutic agents, and vomiting secondary to radiation therapy and toxins... 

The number of clinical studies with A -THC is large and the field has recently been reviewed [ 146, 148] hence, only a few typical reports are mentioned here. In a 1980 study [157], 46 patients (9-70 years old) in a double-blind, crossover study were administered either A -THC (10 mg/m2 orally, three times daily) or prochlorperazine (10 mg, orally, three times daily). A -THC was more active than prochlorperazine, regardless of the emetogenicity of the chemotherapeutic agent, and young patients were more likely to have complete response than older patients. In a 1982 study [158], 27 adults in a double-blind study with A -THC (10 mg/m2, orally five times daily) and metoclopramide (2 mg/kg, i.v. five times daily) were compared. Metoclopramide was more potent than THC both as regards number and volume of emetic episodes. 

Exogenously administered cannabinoids act via both central and peripheral mechanisms to prevent emesis produced by emetic stimuli such as serotonin or chemotherapeutic agents (8,95). 

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