Types of Insulin

Diabetes has been around for a long time. In fact, documentation of symptoms of this condition date back to 1552 BC, when it was mentioned by a physician in ancient Egypt. Described in the 1600s as the “pissing evile,” urination and thirst were the hallmarks of a disease for which there was no treatment. Fast-forward a few hundred years to 1921, when researchers Frederick Banting and Charles H. Best discovered insulin in the pancreatic extracts of dogs. With help from other scientists, insulin was developed into a form suitable for human treatment.

How is insulin made?
Insulin is required for all forms of life (except for certain insects), including worms, fish, and mammals. In fact, the early forms of insulin available for human injection were derived from animal sources, including cows, pigs, horses, and even fish! Some of you might have even injected pork or beef insulin (these are no longer available in the U.S.). However, because the amino acid sequence of animal insulins differs from that of humans, these animal insulins were known to cause allergic reactions.

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Back in the 1980s, a new way to produce insulin was enacted, using a technique called recombinant DNA technology. Scientists were able to genetically alter bacteria or yeast cells to produce pure human insulin in large amounts. As a result of this technology, insulin in the U.S. is much less likely to produce allergic reactions (although some people do have an allergy to insulin). In 1982, pharmaceutical company Lilly introduced the first engineered insulin to the market under the brand name Humulin — this, by the way, was the first recombinant DNA drug in the world.

What are insulin analogs?
Biotechnology didn’t stop with Humulin, however. With the newfound ability to tweak insulin’s DNA, scientists soon developed other types of insulins called insulin analogs. Being able to alter genes allowed scientists to formulate insulins that would work faster or slower than regular old human insulin, making it easier for those with diabetes to better manage their blood sugars. The first rapid-acting insulin to be introduced — by Lilly — was lispro (Humalog) in 1996. Soon thereafter, other analogs were introduced, including aspart (NovoLog), glulisine (Apidra), and the longer-acting analogs glargine (Lantus) and detemir (Levemir). Longer-acting insulin analogs work for roughly 24 hours and have no “peak.”

What are the new insulins on the market?
Insulin technology hasn’t stopped. Over the past couple of years, even more insulins have been introduced. These include:

Toujeo: Actually insulin glargine, Toujeo is a more concentrated insulin (300 units per milliliter; Lantus is 100 units per milliliter). It’s essentially a longer-acting version of Lantus.

Tresiba: Insulin degludec. This comes in two concentrations, U100 and U200, and lasts longer than 24 hours.

Ryzodeg: A combination of insulin degludec 70 units per milliliter and insulin aspart 30 units per milliliter.

And coming soon is Basaglar from Lilly. This insulin is a “biosimilar” version of insulin glargine. It’s biologically similar to glargine (somewhat like a generic version of glargine), but will supposedly have a lower price tag (insulin analogs, as many of you know, don’t come cheap). Basaglar is due to be released this month, according to the FDA.

What about inhalable insulin?
Inhalable insulin, in theory, sounds like a diabetes dream: no more injections! Afrezza is the only inhalable insulin available in the U.S., and it’s an ultra-rapid-acting insulin. This means that someone with Type 1 diabetes still needs to inject long-acting insulin, which means that injections aren’t going away any time soon. It’s not appropriate for anyone with certain lung diseases, such as COPD or asthma, and some in the health-care community are concerned about a possible risk for lung cancer (although there is no proven correlation).

What are pre-mixed insulins?
If you need a simpler insulin regimen, premixed insulins may be for you. Premixed insulin is a combination of a faster-acting and a longer-acting insulin, which means fewer injections. Many of these combination insulins contain NPH, an intermediate-acting insulin. Ryzodeg contains insulin degludec, an ultra-long-acting insulin. While seemingly convenient, the downside of these insulins is that fine-tuning is pretty much impossible, because if you adjust the dose of the insulin to, say, decrease the NPH insulin, you also decrease the faster-acting insulin. However, premixed insulins can be suitable for people with consistent meal and activity patterns, or limited vision or dexterity issues, or for people who are new to insulin and feeling overwhelmed.

What are the options for injecting insulin?
Insulin can be injected using a syringe and a vial of insulin. Syringes come in different sizes and different needle gauges and lengths. Syringes are the most common and least expensive way to inject. However, the newer insulins, such as Toujeo and Tresiba, don’t come in a vial, only in an insulin pen. Insulin pens are becoming more common because they’re easier and more convenient to use than a syringe and vial. Pens may contain a cartridge of insulin that is replaced, or the pen itself may be disposable. In a nutshell, you screw a needle on to the pen, dial up your dose, and inject. The downside is that pens can be expensive, and insurance coverage varies.

The other way to deliver insulin is via an insulin pump. Insulin pumps are small, computerized devices that continuously deliver only fast-acting insulin, but at a constant rate. The wearer “boluses” insulin doses by pressing a button on the pump to deliver insulin at a meal or to correct a high blood sugar. Pumps are primarily used by those with Type 1 diabetes, but many people with Type 2 use them, as well. Using an insulin pump requires insertion of an infusion set under the skin that is changed every few days. In addition, pump-wearers must have the time, commitment, and patience to learn how to properly use their device and adjust basal and bolus rates (along with conducting multiple blood sugar checks and maintaining accurate carb counting).

Today, there are many options for those who take insulin, and no doubt, more insulins will be coming down the pike. If you’re interested in any of the newer insulins or different ways to administer this medicine, be sure to talk with your diabetes educator or health-care provider.

When she’s running with diabetes, Amy Mercer see herself as a tightly controlled science experiment, but when she’s crossing the finish line, she sees herself as a winner. Bookmark DiabetesSelfManagement.com and tune in tomorrow to read more.