Metoclopramide for the treatment of diabetic gastroparesis

Introduction: Gastroparesis is a chronic disorder of the stomach characterized by delayed gastric emptying without mechanical obstruction. Diabetes is the most commonly known cause of gastroparesis. Management of diabetic gastroparesis involves lifestyle modifications, glycemic control, pharmacological drugs, and for refractory cases surgical treatments. Metoclopramide remains the only drug approved by the Food and Drug Administration for diabetic gastroparesis. The aim of this article is to provide a concise review of the pharmacology, clinical efficacy and tolerability of metoclopramide. Areas covered: We searched PubMed using the key words 'metoclopramide', 'diabetic gastroparesis', and 'gastric emptying'. The relevant articles and their bibliography were reviewed. Metoclopramide acts on several different receptors; primarily as a dopamine receptor antagonist, both peripherally improving gastric emptying, and centrally resulting in an anti-emetic effect. Metoclopramide side effects, mostly related to its ability to cross the blood-brain barrier, include drowsiness, restlessness, hyperprolactinemia, and tardive dyskinesia (TD), a movement disorder that may be irreversible. Expert opinion: Metoclopramide carries a black box warning for use >12 weeks due to the risk of TD. However, gastroparesis patients experience chronic symptoms often requiring prolonged treatments. Physicians and patients look forward to FDA approval of new agents for gastroparesis with better efficacy and safety profile.