Overview of Insulin Therapies in Type 2 Diabetes

Dhiren Patel, PharmD, provides an overview of the types of insulin therapy and discusses key factors to consider when assessing whether basal or prandial properties are needed.

Dhiren Patel, PharmD: Regarding the different classes of insulin that exist when managing a patient with diabetes, we have rapid-acting insulin, short-acting insulin, intermediate-acting insulin, and then long-acting insulin. At this juncture, what I see in my practice a lot is the use of rapid-acting insulin as well as basal insulins, and now there’s a shift towards newer-generation basal insulins. And so, that allows you to do a combination of those, and the reason I mentioned basal bolus is because it’s a very common approach that’s used in terms of the management of blood sugars.

Some of the newer-generation basal insulins include Toujeo and Tresiba. Other ones that you may be familiar with include Lantus and Levemir. They provide a basal amount of insulin that pretty much covers you for a 24-hour period. And then, whenever a patient consumes a meal, you need to cover that meal through a rapid-acting or short-acting insulin, which they would use prior to a meal to cover the glucose excursion that the patient would have after consuming a meal. That’s the traditional basal bolus approach when you’re thinking about insulin management.

The short-acting insulins and the intermediate-acting insulins are less seen now for a variety of reasons. They have a little bit more hypoglycemia associated with them. They need to be injected more frequently, and for that reason you’re seeing some of the shift in terms of newer-generation basal insulins.

When we think of insulin therapy, traditionally what happens is a patient would get started on a basal insulin. The reason for that is the basal insulin is going to help bring down a patient’s fasting plasma glucose, and they always say treat fasting first. And so, patients will typically get started on a basal insulin to bring down their fasting plasma glucose.

After a certain point, 1 in 2 patients who are on a basal insulin won’t actually get to goal because it’s done a great job in lowering the fasting plasma glucose, but their postprandial glucose readings are high. In those situations, they’re going to need something else to lower that blood sugar that happens after consuming a meal, and that’s where your rapid-acting and your short-acting insulin becomes very important. Those might usually get added on after a patient has been optimized on a basal insulin. And for that, you might be looking at a patient’s log book and seeing that their fasting numbers in the morning are fine. They’re waking up within range, but their A1C level is still elevated, and if the patient were to check their postprandial glucose after a meal, they’ll probably notice that it is elevated and not within goal. Then you would adjust that dose to that meal, make sure that those excursions don’t happen to them again, and improve glycemic control for that patient.

When you think about insulin intensification, there are a lot of different factors that go into it for patients who are being seen by local pharmacies. It’s very easy to figure out what amount of insulin the patient’s on and how quickly they’re being titrated to their targeted dose to get to that fasting plasma glucose range. But what I also see happen a lot, and where I think pharmacists can intervene, is the exact opposite, where there is too much insulin intensification when we’re talking about basal insulin. You’ll hear about the phenomenon of over-basalization.

So, 1 in 2 patients who are on a basal insulin will actually not get to goal on just basal insulin. They’re going to need something else to treatment intensify outside of just their basal insulin, and that weight-based dosing is around 0.5 to 0.7 units per kg for a patient. The reason I’m mentioning the weight-based dosing is that most doses are not done weight-based. Everyone is taught, and it’s perceived, that insulin has no maxed dose, but there is one. It’s where you’re going to see a rate of diminishing effect in terms of lowering blood sugars. And at that point, it makes sense to add another short-acting or rapid-acting insulin, or to switch to a different class of an injectable and treatment intensify.