ABSTRACT
Two main classes of 5-hydroxytryptamine (5-HT)-related pharmacologic agents have been developed with proven clinical success in the treatment of gastrointestinal disease. Cisapride, a piperidinyl benzamide chemically related to metoclopramide, has 5-HT4 receptor agonist activity and is currently approved in the United States. The clinical trials that form the foundation for recommendation for the use of selected serotonin agonists and antagonists in practice are discussed. 5-HT receptor antagonists have a minimal, if any, role in improving the kinetics of gastrointestinal motility disorders. In fact, the 5-HT3 receptor antagonists have actually been shown to slow colonic transit, with constipation as a predictable side effect in a dose-dependent manner. Metoclopramide, a dopamine antagonist, has some antiemetic properties, but is effective in preventing chemotherapy-induced emesis only when used in high dose. 5-HT antagonists are at least as effective as other available single-agent therapies in the treatment of acute chemotherapy-induced nausea and vomiting, but do not confer any significant benefit compared with traditional agents.
