Rx Update: October 2002

Review of Insulin Products

Mary Ross, R.Ph., M.B.A., Barbara Mutnick, R.Ph., M.H.P., Joan Murhammer, R.Ph.
Peer Review Status: Internally Reviewed

There have been a number of new insulin products introduced in the US for the treatment of diabetes. The onset, peak, and duration of action after subcutaneous injection of the newer products as compared to the other available insulin preparations are listed in the table below. The compatibility of the insulin mixes is also shown.

Insulin Type	Brand Name(s)	Onset (hrs)	Peak (hrs)	Duration (hrs)	Compatible mixed with
Rapid
Aspart	NovoLog®	0.25	0.75-1.5	3-5	NPH
Lispro	Humulog®	0.25	0.5-1.5	5 or less	Ultralente, NPH
Short Acting
Regular	Novolin R® Humulin R® Reg/Iletin II Pork® Velosulin®	0.5-1	2-4	5-7	Lente, Ultralente, NPH
Intermediate Acting
Isophane (NPH)	NPH/Iletin II Pork® Novolin N® Humulin N®	1-3	6-12	24-28	Regular
Lente (zinc suspension)	Humulin L® Novolin L®	1-3	6-12	24-28	Regular
Long Acting
Glargine	Lantus®	1	4-5 (blunted)	24	None
Ultralente (zinc suspension -- extended)	Humulin U®	4-6	16-24	36+	Regular

There are other important aspects to the dosing and administration of the newer insulins. These include:

• Insulin glargine (Lantus®) should NOT be administered IV and cannot be mixed with any other insulin product.
• Insulin glargine is a clear solution, and when it is injected subcutaneously, it forms a precipitate under the skin which results in delayed absorption and a 24-hour effect.
• Insulin glargine is usually administered at bedtime.
• It is easy to mistake Lantus and lente insulin, both verbally and in writing because of look-alike sound-alike names. Therefore, it is imperative to verify which one is prescribed when either one is ordered for a patient.
• When mixing regular insulin, insulin aspart, and insulin lispro be sure to draw them into the syringe first; remember, clear solutions are always drawn up first.
• Insulin aspart and insulin lispro are taken directly before meals. They have a quick onset and short duration of action. Regular insulin does not act as quickly, but lasts slightly longer.
• Insulin aspart can only be mixed with NPH. Insulin lispro can be mixed with ultralente and NPH.
• There is no information on the stability of insulin glargine, insulin aspart, or insulin lispro stored in syringes. They are to be administered immediately after being drawn up.
• Humulin® and Novolin® brands are considered therapeutically equivalent by the Pharmacy and Therapeutics Subcommittee. Therefore, the least expensive brand will be stocked.

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