Metoclopramide — Drug Monograph

Brand names: Reglan, Metozolv

Drug class: Supportive Care Agent

Mechanism of Action

Dopamine D2 receptor antagonist (central CTZ blockade) and prokinetic agent (enhances gastric emptying by sensitizing GI smooth muscle to acetylcholine). At high doses used historically for CINV (≥1–2 mg/kg IV), also antagonizes 5-HT3 receptors. Accelerates gastric emptying, increases lower esophageal sphincter tone, and normalizes gastric motility — mechanisms complementary to central antiemesis.

FDA Indications

• Symptomatic gastroesophageal reflux disease (GERD) — short-term treatment (4–12 weeks)
• Diabetic gastroparesis
• Prevention and treatment of nausea and vomiting associated with emetogenic chemotherapy
• Prevention of postoperative nausea and vomiting
• Facilitate small intestinal intubation

Common Side Effects

• Drowsiness/sedation
• Fatigue
• Restlessness/akathisia
• Diarrhea
• Extrapyramidal reactions (dystonia, akathisia — dose and duration dependent)

Clinical Pearl

High-dose metoclopramide (1–2 mg/kg IV) was the standard antiemetic for HEC in the pre-5-HT3 era. It works better than low doses but always requires diphenhydramine premedication to prevent dystonic reactions. In current oncology, metoclopramide is reserved for breakthrough or rescue CINV when standard agents fail, or for treating opioid-associated gastroparesis. Its prokinetic effect (accelerates gastric emptying) is uniquely beneficial in patients with delayed gastric emptying contributing…

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