Gastrointestinal prokinetic therapy: Serotonergic drugs

Gastrointestinal prokinetic therapy is becoming increasingly important in small animal practice. The first four parts of this five-part Continuing Education series group gastrointestinal prokinetic drugs into four categories; for each category, the mechanisms of action, site of activity, and indications are considered. Part I provided information on the dopaminergic antagonist drugs. Part II dealt with motilin-like drugs. This article, which is Part III, discusses serotonergic drugs, especially cisapride. Part IV will deal with the acetylcholinesterase inhibitors or parasympathetic potentiating drugs. The concluding article will consider the diagnosis and treatment of esophageal, gastric, and colonic motility disorders. Cisapride stimulates gastrointestinal motility at a dosage of 0.1 to 1.0 mg/kg orally every 8 to 12 hours. It is superior to metoclopramide in the treatment of gastroesophageal reflux, delayed gastric emptying, ileus, and constipation. At a dose of 0.6 to 2.6 mg/kg, cisapride may be useful as an antiemetic for patients receiving cis-platinum chemotherapy if other 5-HT₃ antagonists are unavailable.