Review of a new gastrointestinal drug--metoclopramide

The pharmacology, pharmacokinetics, therapeutic and diagnostic uses, toxicity, adverse reactions, and contraindications of metoclopramide are reviewed. Metoclopramide enhances the rate of gastric emptying by (1) augmenting esophageal peristalsis, gastric antral contractions, and small intestine transit time and (2) increasing resting pressures of the lower esophageal and pyloric sphincters. The drug does not stimulate gastric acid secretions. The injectable form is approved for use to facilitate intubation of the small intestine and the passage of barium into the intestine for radiographic procedures. Tablets are approved for the treatment of symptoms associated with diabetic gastroparesis. The drug has been used in the treatment of vomiting of various etiologies. The side effects of metoclopramide are usually mild, transient, and reversible with discontinuation of the drug. They include drowsiness, GI disturbances, extrapyramidal reactions, and increased lactation. Metoclopramide should not be given in combination with MAO inhibitors, tricyclic antidepressants, sympathomimetic amines, or to patients with pheochromocytoma, GI hemorrhage, obstruction, or perforation. Metoclopramide appears to be an effective drug in stimulating the mobility of the upper gastrointestinal tract without increasing gastric secretions. Further studies are needed to assess its value in the treatment of vomiting secondary to anesthesia and chemotherapy, and to assess its precise role in the treatment of diabetic gastroparesis.