Duration of Action of Humalog (Insulin Lispro)
Humalog has a duration of action of 3 to 4 hours in adult diabetic patients. 1
Pharmacokinetic Profile
Humalog (insulin lispro) is a rapid-acting insulin analog with distinct timing characteristics that differentiate it from regular human insulin:
- Onset of action: 5 minutes 1 to 15 minutes 2
- Peak effect: 1 to 2 hours 1, with some sources noting 30 to 90 minutes 2
- Duration of action: 3 to 4 hours 1
This shorter duration compared to regular human insulin (which lasts 6 to 8 hours) 1 is a defining characteristic of rapid-acting insulin analogs like lispro.
Clinical Implications of Short Duration
The relatively brief 3-4 hour duration of Humalog has important practical consequences:
- Late postprandial hyperglycemia risk: The short duration may allow blood glucose to rise 4-7 hours after meals unless basal insulin is adequately replaced 3
- Reduced nocturnal hypoglycemia: The shorter action profile contributes to lower rates of nighttime hypoglycemia compared to regular insulin 4, 2
- Timing flexibility: Humalog should be administered within 15 minutes before meals, in contrast to the 30-40 minute pre-meal timing required for regular insulin 4
Comparison with Other Insulins
The American Diabetes Association guidelines confirm that rapid-acting analogs (including lispro) have a "quicker onset and peak and shorter duration of action than regular human insulin" 1. This pharmacokinetic profile makes lispro particularly effective for controlling postprandial glucose excursions while minimizing the risk of delayed hypoglycemia 1.
Basal Insulin Requirement
Because of Humalog's 3-4 hour duration, patients typically require separate basal insulin coverage to maintain glycemic control between meals and overnight 3. The short action period means that without adequate basal insulin, blood glucose levels can become unstable during gaps between rapid-acting insulin doses 1.