Maintaining Oral Agents After Starting Insulin: What, and for How Long?

Jay H. Shubrook, DO; Amber M. Healy, DO


April 24, 2017

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Jay H. Shubrook, DO: Hello. I am Jay Shubrook, DO, family physician and diabetologist at Touro University, California. We are going to continue our series on practical insulin use for primary care. Today I am happy to be talking with Amber Healy, DO, internist and diabetologist at the Diabetes Institute of Ohio University. Welcome, Amber.

Amber M. Healy, DO: Thank you for having me.

Dr Shubrook: Many of my patients will progress from oral therapies to insulin. They might be taking one, two, or even three oral therapies by the time there is a switch to insulin. How do you progress from oral therapies to insulin?

Dr Healy: In general, my patients are on two to three oral agents before adding insulin. It depends on some of their comorbidities and what meds they may have tried in the past, and how well they are responding to their current medication.

Dr Shubrook: Are there any medications that you really try to keep on board even though you are starting insulin?

Dr Healy: I try to keep metformin, unless there is some contraindication for that patient, such as decreased kidney or liver function or an ejection fraction less than 30%. Medications that I like to stop when people go on insulin are such things as the secretagogues, especially sulfonylureas.

Dr Shubrook: My patients often ask why I am suggesting staying on metformin. To them, it seems that the medicine is not working well enough.

Dr Healy: Metformin has multiple benefits. Not only is it an insulin sensitizer that in some people will lead to some weight loss, but it also has been found to have some anticancer properties. The benefit of leaving it on when you are adding insulin is that sometimes you need less insulin in the patient to get the same control.

Dr Shubrook: It has a benefit even beyond its glycemic effect?

Dr Healy: Absolutely.

Dr Shubrook: You mentioned the sulfonylureas and other secretagogues. What is your concern there?

Dr Healy: My concern is that the patient will have problems with hypoglycemia because secretagogues force the pancreas to secrete more insulin, and when you have that endogenous insulin on top of your exogenous insulin, it can be too much for somebody and leads to hypoglycemia.

Insulin: Are We Waiting Too Long?

Dr Shubrook: What are your triggers for insulin? One of the things that I always worry about is that we wait too long before we start insulin. When do you know to transition from oral to insulin?

Dr Healy: In general, if the A1c is over 8.5% and I have tried other meds that have not worked out well, I will go to insulin. Sometimes when the patient is newer to me and their A1c is 10% or higher, or even in the 9% range, and they are being sent to me for the first time by their primary care doctor, insulin is just the best thing because of its benefit in breaking that glucotoxicity cycle that is so hard to improve in people whose disease has been uncontrolled for so long.

Dr Shubrook: I find that that is really important. You can spend a lot of time on oral therapy and not make much progress. Insulin is certainly the most potent of all the medications.

What about adding oral medications for a patient who is already on insulin? I get that question a lot. Is there any role for oral therapies in patients who are already on insulin?

Dr Healy: Yes, there is. I have had patients who have come in on huge quantities of insulin, and they are not getting the control they should on that much insulin. Sometimes with the correct oral, or sometimes even injectable, medication, such a glucagon-like peptide-1 (GLP1) receptor agonist, you can decrease the amount of required insulin or even make insulin more effective and improve glycemic control.

I had a patient, an older gentleman, who was on almost 200 units of insulin, and he was coming to me because his provider wanted me to put him on U-500 insulin. I put him on pioglitazone, and he ended up requiring less insulin and did not require the concentrated insulin.

I used a similar approach in another patient who was on a fair amount of insulin by initiating a sodium/glucose cotransporter 2 (SGLT2) inhibitor. He began seeing blood sugars under 200 mg/dL that he had not seen in years.

Dr Shubrook: That is a really good point. We typically will go for a couple of oral therapies, then we start insulin. We may want to keep the insulin sensitizer metformin on for the nonglycemic benefits. Even once people are on insulin, particularly those with type 2 diabetes, adding an insulin sensitizer, such as pioglitazone or even an SGLT2 inhibitor, might reduce the insulin burden.

How do patients feel about adding oral medications once they have been on insulin?

Dr Healy: A lot of them are receptive to it because they get tired of taking such large quantities of insulin. Some of them will even ask, "Is there anything else I can take to improve my diabetes?" That is a great time for you to have those types of discussions with your patients. I always take those opportunities to say, "Have you ever been on this?" We talk about the risks and the benefits, and a lot of times they are willing to try it. When they come back, they are really satisfied.

Dr Shubrook: That is great. If I heard correctly, when you transition from oral medications to insulin, sometimes those oral medications should stay on board, particularly if they are not going to contribute to hypoglycemia. We need to continue to think about using oral therapies after insulin to reduce the insulin burden and to get some other nonglycemic benefits.

Dr Healy: Yes, that is correct.

Dr Shubrook: Thank you so much today for your insight and your contributions.


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