Pharm 101: Glucagon

Class

Antihypoglycaemic

Pharmacodynamics

• Produced by alpha islet cells in pancreas. Multiple organ system effects.
• Metabolic:
  • Gluconeogenesis, ketogenesis, glycogenolysis
  • Pharmacological amounts cause release of insulin from normal pancreatic beta cells
• Cardiac:
  • Positive inotropic and chronotropic effect
  • Produces effect similiar to beta-receptor agonists without requiring functioning beta-receptors
• Smooth muscle:
  • Relaxation in large doses

Pharmacokinetics

• Extensively degraded in liver, kidneys, plasma
• Half-life 3-6 minutes (similiar to insulin)

Clinical uses

• Severe hypoglycaemia
  • IV, IM or SC administration
  • 1mg vials
• Diagnosis of endocrine disorders
• Previously first-line in beta-blocker overdose
  • Ability to increase cAMP production in heart independent of beta-receptor function
• Radiology of bowel

Adverse effects

• Transient nausea/vomiting

Precautions/contraindications

• Pheochromocytoma

Further reading

• Nickson C. Pharm 101: Beta-Blocker Overdose. LITFL

References

• Katzung BG. Basic and Clinical Pharmacology. 14e. 2018: 749-751