Insulin: A Diabetes Medication

Written by Corie Richter, PA

The first medication for the treatment of diabetes was insulin, isolated in 1922 by a Toronto team led by Dr. Fredrick Banting. For many years, insulin was the only diabetes treatment—and it was quite the lifesaver when it was first discovered. Before insulin was discovered as a treatment for diabetes, people with diabetes, sadly, couldn't expect to live long.

The First Insulins as Diabetes Medications
After its discovery as a diabetes medication, insulin was mass produced from the pancreas of cows or pigs. This is called bovine (cow) insulin or porcine (pig) insulin, and these animal versions were the only way to make insulin for awhile.

However, problems soon emerged with the new diabetes medication. Individuals found themselves with allergic reactions or sensitivities to one or the other of the insulins, ranging from minor rash to anaphylaxis (a severe reaction leading to death).

Another problem with naturally occurring insulin (bovine or porcine insulin) was its inconsistencies. This is faced by every medication, or even product, that is obtained naturally.

Individual animals produce varying concentrations, and the manufacturing process cannot always control the consistency of concentration. Therefore, while insulin was a step forward in managing diabetes, the forms of insulin available weren't always reliable.

The duration of the original insulin was 6 hours, meaning at least twice daily doses.

Insulin Developments
By the mid-1930s, scientists recognized that the addition of a protein, protamine, and zinc to the subcutaneous mixture of insulin would extend the absorption up to 36 hours—meaning fewer injections. This medication mixture was known as PZI.

In the 1940s, the diabetes world was introduced to an insulin mixture known as NPH, which had a duration midway between its 2 predecessors. The NPH stands for neutral protamine hagedorn—a researcher named Hans Christian Hagedorn discovered that adding protamine to insulin increased its length of effectiveness.

These developments in the insulin and diabetes world meant that people with diabetes could achieve more accurate blood glucose control. They could, for example, take an insulin that provided long-term (several hours) blood glucose control, and they could take an insulin dose that provided more immediate blood glucose control.

Pre-mixed insulins were developed. Instead of drawing insulin from more than one vial, people using pre-mixed insulin could use the same vial that contained combinations of 2 types of insulin—for example, a rapid-acting insulin and an intermediate-acting insulin.

The advent of the common 70%/30% mix gave 70% of the insulin over a longer period of time while the 30% was given for absorption over a shorter period.

Insulin Analogs
In the 1980s, researchers discovered how to reproduce human amino acid sequencing and apply it to the manufacture of insulin, further improving this long-lived diabetes medication. Synthetic insulin is called an insulin analog.

The development of insulin analogs meant that bovine and porcine insulins were no longer needed, although some people do still take them.

Unlike with the animal versions of insulin, there is less likelihood of people being allergic to insulin analogs because they so accurately mimic the body's natural form of insulin (and therefore, the body won't reject it as "foreign").

Insulin: The Most Important Medication for Type 1 Diabetes
Type 1 diabetes used to be called insulin-dependent diabetes, so you can see how important it is to people with type 1 diabetes. Because their bodies don't produce any insulin, they must have this medication.

(We should point out, though, that type 1 diabetes is no longer known as insulin-dependent diabetes because some people with type 2 diabetes may need to take insulin to help them meet their blood glucose goals. So the name of "insulin-dependent" diabetes isn't very accurate.)

The medical research community continues to work diligently to improve insulin and insulin delivery (how people with diabetes get insulin into their bodies).