Insulin Information

Medicine Buzz: Insulin

Renata Fruga (Pharmacy Student), Ashley Davis (Pharmacy Student), William
Kirchain, PharmD, CDE, Director – Xavier University Health & Wellness Center

What is Insulin?

Many people with diabetes both Type 1 and Type 2 need to include insulin in their treatment plan. Insulin is a protein that is made naturally by the body in the pancreas. When a person eats a meal the sugars and fats absorbed from the bowels travel to the pancreas and trigger the release of insulin into the blood. The insulin quickly travels to several parts of the body where it signals a variety of cells to take in these new sugars floating in the blood. Some of this insulin pulse goes to the liver to turn off sugar production and turn on sugar storage, along with fat storage. Still another portion of the insulin goes to muscles and other tissues where it turns on the production of new tissues and muscle fibers.

Types of Insulin

There are several different types of insulin. The different types are designed to dissolve into the blood at different rates. Combing different types of insulin is often needed to get the best control over a person’s blood sugar.

Rapid acting insulins are intended to be used just before a meal and are targeted to control the sugar spike from that particular meal. Short acting insulin also known as regular insulin is targeted to control both the immediate meal plus a few hours after the meal. Intermediate acting insulins like NPH are targeted at controlling the lingering sugar from a meal while primarily keeping the in-between meal blood sugar lower. Long acting insulins are targeted solely at the in-between meal sugar level produced by liver.

The effectiveness of the long acting insulin is best checked by fasting blood sugar readings. The effectiveness of the rapid acting insulins is best checked by readings taken about 2 hours after beginning a meal. Regular and NPH insulins require a mix of fasting and post-meal readings to accurately determine if they are effective.

How Does Insulin Work?

Insulin is a protein. Like all other proteins if taken orally insulin is broken up into amino acids in the stomach. Like many other proteins it is too large to make it across the skin on its own. So in order to get it into the body insulin must be injected. Because insulin is a protein it is sensitive to heat, light and excessive cold. In the dark refrigerator insulin will last quite a while (note the expiration date on the side of the vial) but at room temperature a vial of insulin is good for about 30 days. The same goes for the insulin inside insulin pen injectors.

Types of Insulin

Drug Name Category When to Inject Onset Time to Peak Duration
Lispro Rapid-Acting 5-15 min. before a meal 15-30 min. 0.5-2.5 hrs. Less than 5 hrs.
Aspart Rapid-Acting 5-15 min. before a meal 12-13 min. 1-3 hrs. 3-5 hrs.
Glulisine Rapid-Acting 5-15 min. before a meal 12-30 min. 1.6-2.8 hrs. 3-4 hrs.
Regular Short-Acting 30 min. before a meal 30 min. 2.5-5 hrs. 4-6 hrs.
NPH Intermediate 30 min. before a meal 1-2 hrs. 4-12 hrs. 14-24 hrs.
Lente Intermediate 30 min. before a meal 0.5-1.5 hrs. 4-11 hrs. 12-22 hrs.
Ultralente Long-Acting Once daily; morning or night 4-6 hrs. 8-20 hrs. 24-28 hrs.
Glargine Long-Acting Once daily; morning or night 1 hr. No Peak 24 hrs.
Detemir Long-Acting Once daily; morning or night 3-4 hrs. No Peak 24 hrs.
Lispro & NPH Mixed Insulin 5-15 min. before a meal 15-30 min. 0.5-2.5 hrs. Less than 5 hrs.
Aspart & NPH Mixed Insulin 30 min. before a meal or at bedtime 0.5-1 hr. 1.5-4.5 hrs. 7.5-24 hrs.
Regular & NPH Mixed Insulin 30 min. before a meal 30 min. 2-12 hrs. 18-24 hrs.

Types of Insulin

Generic Name US Trade Names* UK/EU Trade Names Other Trade Names
Lispro Humalog Humalog, Liprolog
Aspart Novalog NovoRapid***
Glulisine Apidra Apidra, Apidra Optiset, Apidra Solostar
Regular Humulin Actraphane, Actrapid
Insulin/Zn Susp. Semilente
NPH Humulin N, Novolin N Protaphane Humacart
Pork NPH NPH Illentin II Umuline Protamine Isophane
Lente Lente, Lente-Illetin II Insulatard Monotard, Lentard, Zinulin
Glargine Lantus, Solostar Lantus***, Optisulin Lantaus
Detemir Levemir Levimir***
Lispro & NPH Humalog 75/25 Humalog Mix, Liprolog Mix 25**
Aspart & NPH Novolog 70/30 NovoMix 30**, Novorapid
Regular & NPH Humulin 70/30 Humulin M3, Insuman Comb 15 Humacart 3/7, Humulin 3/7
Regular & NPH NovoLin 70/30 NovoLin Mix 70/30, Mixtard 30 **, Genuslin 30**

* U.S. Trade Names are the most common found in Mexico and most of Latin America, but European and Asian Trades occasionally are found there as well.

** Liprolog 25 = Humalog 75/25; NovoMix 30 = Novolog 70/30, BEWARE in Europe NovoMix 70, Mixtard 70, Liprolog 75 are the opposite of our 70/30 or 75/25.

*** Most Common Trade Name in UK, EU, Latin America and Asia, Including India.

Caution about doses… In the United States, when you ask for insulin you are usually dispensed what we call “U-100” insulin. U-100 means that there are 100 Units of insulin (no matter what type) in 1 milliliter. In some parts of the world you will find insulin in other strengths, U-500 and U-40. This should be marked on the insulin vial. Be sure and ask the pharmacist for U-100 [insert trade name] Insulin.