Insulin helps regulate blood-sugar levels throughout the day and night, a key to managing diabetes. People with type 1 diabetes (T1D) rely on insulin therapy to help manage their blood-glucose levels. The food they eat, stress, illness, excitement and several other factors can all affect glucose levels, necessitating insulin for stabilization.
There are many types of insulin that can be administered in several ways.
Types of insulin
Premixed insulin is just that—a preexisting mixture of long-acting insulin that manages blood-glucose steadily throughout the day and short-acting insulin that helps stabilize glucose levels after mealtimes.
(Examples: Humalog Mix 75/25 and Novolog Mix 70/30)
This type of insulin is typically taken approximately 30 minutes prior to meals to offset effects on blood-sugar levels and is combined with long-acting insulin for T1D management.
Intermediate-acting insulin manages blood-glucose elevations for about half of the day or overnight. This type of insulin is typically combined with rapid- or short-acting insulin and is usually taken twice daily.
Long-acting insulin is most often combined with rapid- or short-acting insulin. It manages glucose levels for a full day.
(Examples: Lantus, Levemir)
This type of insulin is often taken right before a meal or snack to offset the carbohydrate intake. It is paired with a long-acting insulin.
(Examples: Apidra, Humalog, Novolog)
How insulin is administered
Injections are needed multiple times throughout the day, though frequency varies on a case-by-case basis and typically involves a combination of both rapid- or short-acting insulin paired with a long-acting insulin. Injections are typically administered to the thigh, buttocks, abdomen or upper arms.
Insulin pumps deliver insulin throughout the day (basal insulin) and large amounts of insulin (bolus) to cover meals or correct high glucose levels. Most people use rapid-acting insulin in their pumps. Insulin pumps are often worn on the hip and can be detached from the infusion site (where the temporary needle or tube enters the body). Sites are typically in the upper thigh, abdomen or along the tricep.
In mid-2016, the FDA approved the first largely automated insulin dosing system known as an artificial pancreas (AP) system. It is a hybrid closed-loop system that requires minimal user intervention. AP systems combine the technology of an insulin pump with that of a continuous glucose monitor (CGM). This pump/CGM combination is typically connected to the body in the same locations as a standalone pump.
Side effects of long-term insulin use
There are a few direct side effects of insulin usage. When dosing is off or carbohydrate intake is miscalculated, people with T1D may experience hypo- or hyperglycemic episodes. These states may result in headaches or flu-like symptoms. People with T1D may also experience itching, loss of fat at the insulin injection site, pain and rash or redness at injection or pump/CGM sites.