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NovoLog Mix 70/30 Confusion

Jul 21, 2014

When prescribing NovoLog® Mix 70/30 analog insulin, health care professionals may write an unclear prescription, or if using an EMR system, inadvertently select Novolin® 70/30 human insulin instead. Be on the lookout for these errors. Read on for a breakdown of the key differences between these 2 types of insulin. Before the new “insulin pens” came out, there were four types of insulin: rapid-acting, short-acting, intermediate-acting, and long-acting.

When it comes to the pre-mixed insulins, like Novolog 70/30, there are fewer differences between the brands (for example, Novolog versus Novolin)….


Whether contained in a bottle or in a pen, the premixed insulins all contain a combination of both an intermediate-acting insulin and a short-acting insulin. The numbers on the bottle or pen refer to the percentage of each type of insulin contained in the mixture. That means both Novolin 70/30 and Novolog 70/30 contain a mixture that is 70% intermediate-acting insulin with 30% short-acting insulin.

However, Novolin 70/30 takes slightly longer to begin working than Novolog 70/30, which has a rapid onset. Both Novolin 70/30 and Novolog 70/30 may last up to 24 hours in the system.

Novolin® 70/30 is not available in a pen. Novolin is the brand name given to all human insulins made by Novo Nordisk. Under this brand are specific types of insulin such as regular, nph, and 70/30. Novolog insulin is a synthetic recombinant insulin that is very rapid acting. You may often get this question because novolog is more expensive than any of the novolins. However, they cannot be substituted for each other.

Two euglycemic clamp studies assessed glucose utilization after dosing of healthy volunteers. NovoLog Mix 70/30 has an earlier onset of action than human premix 70/30 in studies of normal volunteers and patients with diabetes. The onset of action is between 10-20 minutes for NovoLog Mix 70/30 (insulin aspart protamine and insulin aspart (rdna origin)) compared to 30 minutes for Novolin 70/30. The mean ± SD time to peak activity for NovoLog Mix 70/30 (insulin aspart protamine and insulin aspart (rdna origin)) is 2.4 hr ± 0.8hr compared to 4.2 hr ± 0.4 hr for Novolin 70/30. The duration of action may be as long as 24 hours.

Lesson Learned:

Mistakenly switching pre-mix insulins without guidance may cause serious consequences for your patients. Take special care when prescribing by hand or by EHR.