NCIt definition : The hydrochloride salt of the substituted benzamide metoclopramide, a para-aminobenzoic
acid (PABA) derivative that is structurally related to procainamide, with gastroprokinetic
and antiemetic activities. Metoclopramide binds to dopamine 2 (D2) receptors in the
peripheral nervous system (PNS), antagonizing dopamine-mediated relaxation of gastrointestinal
smooth muscle and promoting gastroprokinesis; the pyloric sphincter and the duodenal
bulb are relaxed, peristalsis of the duodenum and jejunum increase, and gastric emptying
and intestinal transit accelerate. This agent may also increase the resting tone of
the lower esophagus sphincter (LES), preventing acid reflux. In the central nervous
system (CNS), metoclopramide antagonizes D2 dopamine receptors in the chemoreceptive
trigger zone (CTZ) of the medulla, thereby preventing nausea and vomiting.;
Alternative definition : NCI-GLOSS: A drug that increases the motility (movements and contractions) of the
stomach and upper intestine. It is used to treat certain stomach problems and nausea
and vomiting caused by chemotherapy. It is a type of antiemetic and a type of motility
agent.;