Exenatide

From a kinetic standpoint, CYP-mediated drug interactions are generally not a major concern because these medications are metabolized through proteolytic degradation rather than the hepatic CYP enzymes.

Exenatide is somewhat of an exception though because it does undergo substantial renal elimination, but for most of the GLP-1s, dose adjustments are generally unnecessary in patients with either hepatic or renal impairment.

I do wanna jump in and mention that there are a few clinically relevant drug interactions worth remembering.

So, uh, tirzepatide, also branded as Mounjaro or Zepbound, uh, actually slows gastric emptying enough to reduce the absorption of oral estrogen-containing contraceptives, um, so that decreases estrogen peak concentrations by roughly fifty-five to fifty-nine percent.

The key intervention that allowed GLP-1 RAs to become viable as medications was a series of structural modifications that markedly extended the half-life.

In 2005, exenatide, sold as Bayeta, was the first injectable GLP-1 RA medication worldwide to receive United States Food and Drug Administration, or FDA approval, for the treatment of type 2 diabetes.

Exenatide has a modified amino acid sequence, making it resistant to DPP-4 degradation with a half-life of 2-4 hours, suitable for twice-daily administration under the skin.

In 2009, liraglutide, sold as Victoza from Novo Nordisk, was granted approval by the European Medicines Agency, followed by US FDA approval in January 2010 for managing type 2 diabetes.

I want you to think about it, the, like the iPhone.

We have the original iPhone, right, iPhone 1, and that was Byetta.

Um, it was Exenatide, that's the initial in 2005.

Okay.

Oh, maybe not in the, in this scenario.

[laughs]

They'd still be expensive, even the, the, the Byetta, right? Because we don't have any generics yet.

Okay.

Now, this paper was published in 2023.

Exenatide has subsequently been discontinued.

not because of safety factors, but because they're simply better drugs that, you know, from the standpoint of weight management.

But there are studies, there was a nice paper published in 2025 in JAMA Neurology from the VCU that looked at over a thousand individuals with idiopathic intracranial hypertension.

Two exceptions, and they're the older drugs.

Exenatide and Elixacinib.

This one's a mouthful.

Lixasenatide.

Did you ever hear about these things before that or no?

Well, I think as a dietician I ha- I had awareness of like Ozempic and Byetta and Victoza from like my patients-

Mm-hmm

... with diabetes, right? And I did work a little while in a bariatric center where the surgeon would give some folks Saxenda.

Yeah.

Byetta came out in 2001, and we've been- Prescribing that and

And it's primarily been used for people with, with-

Diabetes

It's just to say that it's not happening right now, okay? It might certainly take much longer to get the level of evidence that you would need.

For example, you know, most people don't realize that the first GLP to actually get approved in a person was Byetta in the early 2000s.

So we've had GLP-based medicines for almost twenty years now.

I think that's sort of the history that people need to understand, is that in the '80s, GLPs were discovered.

Trials, biotech, all the ordinary slog of turning a molecule into an actual medicine.

The Healer Monster's molecule design was directly copied to produce a synthetic drug they branded Byetta.

They read the molecule's sequence and built it from scratch in a lab.

approved in 2005 for type 2 diabetes.