Pharm 101: Metoclopramide

Class

Anti-emetic

Pharmacodynamics
  • 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
Pharmacokinetics
  • X
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.

Precautions/contraindications
  • X
Further Reading
Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS CCPU (RCE, Biliary, DVT, E-FAST, AAA) Rob is an Emergency Medicine Advanced Trainee based in Melbourne, Australia. He has special interests in medical education, ECG interpretation, and the use of diagnostic and procedural ultrasound in the undifferentiated and unwell patient.

Follow him on twitter: @rob_buttner | ECG Library |

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.