Types of Insulin Formulations for Type 1 and Type 2 Diabetes

Diana Isaacs, PharmD, BCPS, BCACP, BC-ADM, CDCES: I want to discuss some of the different types of insulin formulations that are on the market because there are tons of options, which is amazing. We’ve come a long way from our older insulins, which didn’t have the best kinetic profiles and were a little bit harder to use. Natalie, can you tell us a little bit about some of the different types of insulin formulations that are available for people with type 1 and type 2 diabetes?

Natalie Bellini, DNP, FNP-BC: There is background insulin that we need to hold blood sugar steady. The way I teach this to patients is that if you woke up with a blood sugar reading of 150 today and you kept just taking your basal every day, didn’t run a marathon, didn’t get sick, didn’t give an injection of steroids, but you just kind of lived your life and did your regular duties, then one day, if you never ever ate again, you’d die of starvation with the same blood sugar. It’s supposed to hold you steady. We all know as clinicians that’s not exactly what would happen in the end, but they need to understand that, and they look at you and say, basal is the background, all-the-time insulin, and then there’s mealtime insulin. So, there’s some variety in basal. There’s basal that lasts up to 42 hours, and it can be given once a day at any time of day. There’s basal that acts a little shorter than that, and we sometimes give it twice a day if we do not have such great coverage of the whole 24 hours. There’s some variety in the basal rate, and in the basal options themselves. A lot of the basal is dictated by insurance. Sometimes, I’ll want to use something that I can’t use, and there’s back and forth. Then, there’s mealtime insulin. For type 1s, when patients are eating almost any amount of carbohydrate, they need to give mealtime insulin. For type 2s, sometimes we can use no mealtime insulin and sometimes we need to use mealtime insulin. It depends on their disease process. How much can that pancreas still do? There is regular insulin that we can use. There is rapid-acting, and then there’s ultra-rapid acting. Each one is inhaled, and those insulins act a little bit more quickly depending on their pharmacokinetics and pharmacodynamics.

Diana Isaacs, PharmD, BCPS, BCACP, BC-ADM, CDCES: That’s a great overview. We definitely like that in terms of basal insulin, things have really evolved. First, we had NPH [neutral protamine Hagedorn], which had a peak and made it more likely to have hypoglycemia. Then, we developed glargine and detemir, but we know those don’t always last 24 hours. Like you said, now we have the insulins that last up to 42 hours, like glargine U300 and degludec. Being studied right now is icodec, a weekly insulin. In terms of background insulin, we’ve made so much headway. With mealtime insulin, it’s been a little bit interesting. We started off with regular insulin, which we know has a lot of barriers because it needs to be injected 30 minutes before eating in order to peak and work with the right timing. That’s really tough to know exactly and plan out when you’re going to eat in 30 minutes. That was a challenge. All of these efforts have been made to have more rapid-acting insulins, which have certainly helped, but unfortunately, they’re still not quite as fast as we would like them to be. Rapid-acting insulins generally require a dose 5 to 15 minutes before eating, and it depends on the type of food, too. If you’re going to have a bowl of cereal on an empty stomach, that is going to shoot the glucose up very quickly, so even with a rapid-acting insulin you may have to re-bolus 20 to 30 minutes or more beforehand to get that right timing to work. For that reason, they came out with ultra-rapid. There’s a faster aspart and then lispro-aabc, which is a faster form of insulin lispro. Those are a little bit faster, but they only work a few minutes faster. In terms of duration of action in the body, they still are around the same. Most of their actions are done by 4 hours but could work up to 5 hours.

Transcript edited for clarity