Insulin Pump Therapy

Chemical Identity

Property	Value
Compatible Insulin	Lispro, aspart, glulisine
Delivery	Continuous SC infusion
Reservoir	200-300 units
Catheter	6mm or 9mm steel or Teflon

Structure

Insulin pumps deliver rapid-acting insulin through a subcutaneous catheter (infusion set) connected to a reservoir. Modern pumps include tubed pumps (with remote tubing) and patch pumps (adhered directly to skin). Only rapid-acting insulin analogs are used in pump therapy.

Mechanism of Action

Pumps deliver micro-doses of rapid-acting insulin continuously (basal rate) and on-demand (bolus) for meals. This provides more physiological insulin delivery than multiple daily injections, with programmable basal rates throughout the day and customizable bolus delivery patterns.

Clinical Applications

• Type 1 diabetes: Gold standard for insulin delivery in motivated patients
• Type 2 diabetes: When MDI fails or for patients seeking flexibility
• Pregnancy: Tight glycemic control requirements
• Hypoglycemia unawareness: Reduced severe hypoglycemia
• Closed-loop systems: Integration with CGM for automated delivery

Pharmacokinetics

• Onset: 15-20 minutes (rapid-acting insulin)
• Basal delivery: 0.025-35 units/hour
• Bolus delivery: 0.025-25 units
• Infusion site change: Every 2-3 days
• Absorption: More consistent than MDI

Safety and Side Effects

Infusion site reactions, catheter occlusion (hyperglycemia/DKA risk), skin infections, lipodystrophy, and pump malfunction. Diabetic ketoacidosis risk if insulin delivery interrupted.

References

• Pickup, J.C., & Sutton, A.J. (2008). Severe hypoglycemia and glycemic control in type 1 diabetes. Diabetes Care, 31, 915-919.
• Bergenstal, R.M., et al. (2010). Threshold-based insulin pump interruption. New England Journal of Medicine, 363, 1463-1474.