What is the dose of glucagon (intravenous (IV) or intramuscular (IM)) for intestinal obstruction?

Glucagon Dosage for Intestinal Obstruction

For intestinal obstruction, the recommended dose of glucagon is 1 to 5 mg administered intravenously over 5 minutes, followed by an infusion of 5 to 15 mg/min titrated to clinical response. 1

Dosage Details by Route of Administration

Intravenous (IV) Administration

• Initial bolus dose: 1-5 mg IV given over 5 minutes
• Maintenance infusion: 5-15 mg/min titrated based on clinical response
• For children: 20-30 μg/kg (maximum 1 mg) 1

Intramuscular (IM) Administration

• IM administration is possible but has significant drawbacks compared to IV administration:
  • Delayed onset of action (11.6 minutes for IM vs. 65 seconds for IV) 2
  • Less reliable effect with greater inter-individual variations 2
  • Shorter duration of effect (17.7 minutes for IM vs. 23.3 minutes for IV) 2

Clinical Considerations

Mechanism of Action

• Glucagon relaxes smooth muscle in the gastrointestinal tract, reducing peristalsis and relieving intestinal obstruction
• The effect is most pronounced in the upper GI tract and less marked in the colon and rectosigmoid 3

Onset and Duration

• IV administration provides rapid onset (approximately 65 seconds) 2
• Maximum effect duration is approximately 23-28 minutes depending on dose and individual response 2
• For prolonged effect, continuous infusion may be necessary

Monitoring

• Monitor blood glucose levels as glucagon can cause transient hyperglycemia
• Watch for nausea and vomiting, which are the most common side effects 4

Special Considerations

Contraindications

• Relative contraindication: Insulin-dependent diabetes mellitus 3
• Use with caution in patients with cardiac conditions as high doses may affect heart rate

Combination Therapy

• For enhanced and prolonged effect, consider combination with anticholinergics like hyoscine N-butylbromide 2
• Combined IV glucagon with IM hyoscine provides early onset (65 seconds) with extended duration (31 minutes) 2

Common Pitfalls to Avoid

1. Using too low a dose (less than 0.1 mg) may be ineffective for intestinal obstruction 5
2. Administering IM when IV access is available (IV is faster and more reliable)
3. Failing to monitor for hyperglycemia, especially in diabetic patients
4. Not preparing for potential nausea/vomiting side effects

For malignant bowel obstruction specifically, octreotide may be considered as an alternative or adjunct to glucagon, particularly when gut function is no longer possible 1.