Pharm 101: Metoclopramide



  • Pro-kinetic agent
  • Dopamine (D2) receptor antagonist with peripheral and central actions
  • Peripheral:
    • Increases oesophageal motility
    • Increases lower oesophageal sphincter pressure
    • Increases gastric emptying
    • Activation of dopamine receptors in the gastrointestinal tract inhibits cholinergic smooth muscle stimulation, thus D2 blockade acts as a pro-kinetic mechanism
  • Central:
    • Potent anti-nausea and anti-emetic agent
    • Via D2 blockade in chemoreceptor trigger zone (CTZ) of medulla
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Clinical uses
  • GORD
  • Impaired gastric emptying
  • Anti-emetic
  • Postpartum lactation stimulation (domperidone)
Adverse effects
  • Relate to central dopamine antagonist action
  • CNS:
    • Restlessness, drowsiness, insomnia, anxiety, agitation
    • Common (10-20%), especially in elderly
  • Extrapyramidal effects:
    • Acute dystonia, akathisia, parkinsonian features
    • Tardive dyskinesia* with chronic dosing
    • Due to central dopamine blockade
    • More likely with higher doses and long-term therapy
  • Hyperprolactinaemia, galactorrhoea

*Late occurring syndrome of abnormal movements which is a common complication of long-term neuroleptic or metoclopramide treatment. Caused by relative cholinergic deficiency secondary to supersensitivity of dopamine receptors.

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Further Reading

Pharmacology 101

Top 200 drugs

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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