What Is a GLP-1 Agonist?
I get so many questions about all the type 2 diabetes medications being used off-label for people with type 1 diabetes. More and more people with type 1 diabetes are using drugs meant for type 2 diabetes in addition to insulin.
The results will, ultimately, vary from person to person. But it’s definitely something you should be aware of if you’re a person with type 1 diabetes.
The first thing to know is that carbohydrate metabolism is so much more complex than just insulin or even the pancreas alone. First thing’s first. Let’s talk incretin.
Incretins are a group of metabolic hormones that are released from our small intestine within minutes of eating. GLP-1 (glucagon-like peptide-1) and GIP (gastric inhibitory peptide or glucose-dependent insulinotropic polypeptide) are the two main ones.
One of their many functions is to stimulate the secretion of insulin in the pancreas (glucose control) and decrease food intake by decreasing gastric emptying (you feel fuller faster and for longer periods of time).
The incretin effect -- or, the fact that oral glucose intake stimulates a greater insulin response than IV glucose intake -- occurs because there are so many other hormones released by our GI system that also impact insulin action and carbohydrate metabolism! These other hormones get dysregulated in diabetes (in both type 1 diabetes and type 2 diabetes).
GLP-1: Glucagon-Like Peptide-1
GLP-1 is an incretin made by the small intestine and released in response to food intake. It increases insulin release, decreases glucagon release, slows gastric emptying and decreases appetite.
All of this helps insulin work to better curb spikes after meals.
GLP-1 agonists are synthetic drugs (weekly or daily injectables or daily pills) that do just the same! Common side effects are nausea, vomiting and weight loss, but its main impact is reducing insulin needs and those postprandial (post-meal) blood sugar excursions!
The brand names for them are Victoza, Saxenda, Ozempic, Byetta, Bydureon, and -- most recently -- Rybelsus, the first-ever GLP-1 agonist in pill form.
GLP-1 agonists are not first line therapy and are usually used in combination with something else (like insulin or metformin) to provide a modest decrease in A1c. They work on the same pathway as DPPIV inhibitors (which stop the breakdown of endogenous GLP-1) but there is no synergistic effect if you use them both at once.
GLP-1 agonists are being used with increasing frequency in people with type 1 diabetes (T1D) because it’s one of the pathways that is still mostly intact in a person with T1D.
As rates of insulin resistance, metabolic syndrome, and overweight and obesity (aka hallmarks of type 2 diabetes) in T1Ds rise yearly, we find ourselves with more overlap between the disease processes, and thus, more overlap with treatment!
It is super important to know how and why guidelines and recommendations for people with type 2 diabetes still can apply to people with type 1 diabetes. Type 2 diabetes drugs can be a complementary piece of the puzzle for some T1Ds! So stay informed, do your research, and empower yourself!