Fast-acting insulin replaces the surge of insulin that a healthy pancreas would release at mealtime. In contrast, long-acting insulin mimics the low-level flow of insulin normally released between meals and overnight.
In this way, long-acting insulin works to establish a healthy baseline blood sugar level for the body to work around.
Using long-acting insulin
Long-acting insulin cannot be ingested so an injection using a needle and syringe is a common delivery method.
Long-acting insulin cannot be delivered in pill form because it would be broken down in the stomach.
Instead, it must be injected into the fatty tissue under the skin. From here, it can be gradually released into the bloodstream.
There are different ways of injecting the insulin, and different sites you can use.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, there are a few ways to deliver long-acting insulin. These include:
- Needle and syringe: a dose of insulin is drawn from a vial into a syringe. Different types of insulin must not be mixed in the same syringe.
- Pen: this can be loaded with a cartridge containing a premeasured dose, or prefilled with insulin and discarded after use.
- Injection port: a short tube is inserted into the tissue beneath the skin. Insulin can be delivered using either a syringe or a pen. This only requires the skin to be punctured when the tube needs to be replaced.
Long-acting insulin can be injected into the abdomen, upper arms, or thighs.
Abdomen injections deliver insulin into the blood most quickly. The process takes a little more time from the upper arms, and it is even slower from the thighs.
It is important to stay consistent with the general injection area, but the exact injection site should be rotated frequently. Repeat injections at the same spot on the skin can cause lumps to develop under the skin, making it harder for the insulin to work.
Long acting insulin may be injected into the thigh and upper arm but abdomen injections are most effective.
Each type of long-acting insulin has its own suggested dose. These vary depending on whether the diabetes is type 1 or type 2, as well as for people who have never used insulin before.
When a person is starting to use new insulin, it is recommended that they begin with a smaller percentage of the target dose.
This is so that the body has time to adapt to the drug. That dosage is then gradually increased under the guidance of a doctor.
Long-acting insulin dosage may also be adjusted if diet or amount of daily physical activity changes, or if a person becomes ill. This is because these factors all affect blood sugar levels.
Adjustments can also be made to address any negative reactions to insulin, such as weight gain.
Finding the ideal long-acting insulin regimen is a trial and error process that requires careful monitoring of blood sugar levels.
How it works
According to the American Diabetes Association, the periods that long-acting insulin works for differs from insulin that is faster-acting in three main ways:
- Onset: how quickly a dose of insulin begins to work. Short and rapid-acting insulin starts to lower blood sugar levels within 15 to 30 minutes. Long-acting insulin takes effect several hours after injection.
- Peak time: when a dose of insulin has its strongest effect. Rapid and short-acting insulin peaks at around one to three hours after injection. Long-acting insulin does not have a peak time. It works to lower blood sugar levels at a fairly stable rate throughout the day.
- Duration: how long the effects of an insulin injection last. Faster-acting insulin can control blood sugar levels for only a few hours. Long-acting insulin can work for around 24 hours or more, depending on drug type.
Long-acting insulin cannot stabilize post-meal blood sugar spikes. So, it is usually necessary for people with type 1 diabetes to supplement their long-acting insulin regimen.
They can do this by injecting short-acting or rapid-acting insulin directly before eating.
The FDA recommends three forms of insulin.
When scientists create long-acting insulin, they change the structure of natural insulin. This is so that it can be absorbed into the bloodstream more gradually.
The United States Food and Drug Administration (FDA) explain that there are three forms of long-acting insulin currently on the market:
Below is a summary detailing how each of these work.
This insulin works over the course of the day. Here are some additional details about how it works:
- Duration: 18 to 24 hours.
- Administration: can be taken once or twice daily, at the same time each day.
- Brand name: Levemir.
When injected, insulin glargine forms clusters in the fatty tissue beneath the skin. These clusters break down slowly, so that small amounts of insulin are released into the bloodstream gradually.
- Duration: up to 24 hours.
- Administration: taken once daily, at the same time each day.
- Brand names: Lantus, Toujeo, and Basaglar.
This type of insulin works by slowing down the rate at which insulin molecules are absorbed into the bloodstream.
- Duration: up to 42 hours.
- Administration: taken once daily, and it can be at different times each day.
- Brand name: Tresiba.
According to an article recently published in Business Insider, Basaglar is currently the most affordable brand of degludec long-acting insulin.
Alternatives to injections
Insulin replacement therapy is not always necessary for people with type 2 diabetes. However, it is unavoidable for people with type 1 diabetes, as their bodies can no longer naturally produce insulin.
Long-acting insulin is not the only option for stabilizing blood sugar levels throughout the day. The main alternative currently available is the insulin pump.
The pump delivers small amounts of insulin into the fatty tissue under the skin, working to mimic the way that the pancreas works. The pump is unable to monitor blood sugar levels, so the user must press a button for insulin to be released before each meal.