While there were minor differences between regular insulins derived from animal sources as compared to human insulin, two new forms of insulin (Humalog and NovoLog) are sufficiently different from "regular insulin" to require special considerations. Humalog and NovoLog are NOT regular insulin.

Regular human insulin (sold under the brand names Humulin R and Novolin R) has replaced animal (pork and beef)-derived insulin products. Regular human insulin is slowly absorbed after subcutaneous injection, resulting in an onset of glycemic action in 30 minutes, with a peak effect in 1-3 hours and a duration of up to 8 hours.

Humalog (insulin lispro) and NovoLog (insulin aspart) are human insulin analogues that are designed to be more rapidly absorbed after subcutaneous injection. As a result, both Humalog and NovoLog have a faster onset of glycemic action and a shorter duration of action than does regular human insulin. Humalog and NovoLog have an onset of glycemic action within 15 minutes and a peak effect within 30-35 minutes. For the hospitalized patient, these differences are significant and a change in practice is required for the safe and effective use of Humalog and NovoLog.

Important Considerations:

• Humulin R and Novolin R are not interchangeable with Humalog or NovoLog.
• The administration of Humalog or NovoLog must be immediately followed by a meal. The start of the meal should occur within 5-10 minutes of administration to reduce the risk of hypoglycemia.
• Humalog and NovoLog may be mixed with other longer-acting insulins including Novolin N and Humulin N.

For additional information, please contact your pharmacist.