What is the recommended dose and administration of glucagon (Glucagon) for reducing bowel motion in Magnetic Resonance Imaging (MRI) procedures?

Glucagon Dosage for Reducing Bowel Motion in MRI Procedures

For MRI procedures, the recommended dose of glucagon is 0.5-1 mg administered intravenously to reduce bowel peristalsis and motion artifact. 1

Dosing and Administration Protocol

Standard Dosing

• Intravenous administration:
  • 0.5 mg IV for most MRI examinations 1
  • Up to 1 mg IV may be used if required for adequate bowel relaxation 1
  • For stomach imaging specifically: 0.5 mg IV is recommended as the stomach is less sensitive to glucagon's effects 1

Timing of Administration

• Administer immediately before the MRI sequence requiring bowel immobility
• Onset of action:
  • IV administration: 65 seconds (average) 2
  • Peak effect: 1-2 minutes after IV administration 3

Duration of Effect

• IV glucagon provides approximately 18-23 minutes of aperistaltic effect 4, 2
• This is significantly longer than hyoscine butylbromide (Buscopan), which provides only about 6-7 minutes of aperistalsis 4

Technical Considerations

• Glucagon should be reconstituted with the provided 1 mL of diluent 1
• Swirl the vial gently until completely dissolved with no visible particles 1
• The reconstituted solution should be clear and water-like in consistency 1
• Use immediately after reconstitution 1
• Discard any unused portion 1

Clinical Advantages

• Glucagon achieves more reliable aperistalsis than hyoscine butylbromide, with 100% success rate compared to 50% for hyoscine 4
• Provides improved mucosal coating and increased distention of the stomach and duodenum 3
• Particularly useful for MR enterography, where reduction of peristalsis is essential for image quality 5

Special Considerations

Alternative Administration Routes

• If IV access is unavailable, intramuscular administration can be used:
  • 1-2 mg IM (typically 10 minutes prior to the procedure) 1
  • Note that IM administration has a delayed onset (approximately 11.6 minutes) compared to IV 2

Combination Therapy

• For extended procedures requiring longer aperistalsis:
  • Consider combination of IV glucagon with IM hyoscine butylbromide for early onset and sustained effect (approximately 31 minutes) 2

Precautions and Contraindications

• Contraindications:

  • Pheochromocytoma (risk of substantial blood pressure increase) 1
  • Insulinoma (risk of hypoglycemia) 1
  • Glucagonoma 1
  • Known hypersensitivity to glucagon or excipients 1
  • Insulin-dependent diabetes mellitus (relative contraindication) 6

• Monitoring:

  • After the procedure, provide oral carbohydrates to patients who have been fasting, if compatible with the diagnostic procedure 1
  • Be aware that higher doses (2 mg) produce a higher rate of nausea and vomiting 1

Cost Considerations

• While glucagon is more expensive than hyoscine butylbromide, its superior reliability in achieving aperistalsis may justify its use for optimal image quality 7

By following these guidelines, radiologists can optimize bowel relaxation during MRI procedures, resulting in improved image quality and diagnostic accuracy.