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 (UWA) CCPU Emergency Medicine Trainee with interests in medical education, ECG interpretation, and the use of point-of-care ultrasound in the undifferentiated patient. Co-author of the LITFL ECG Library | Twitter

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