Exenatide
Exenatide (Byetta, Bydureon) was the first GLP-1 receptor agonist approved for type 2 diabetes, derived from exendin-4 in Gila monster saliva. Available as twice-daily and once-weekly formulations, it lowers glucose and weight modestly, with a long track record in humans.
01 Overview
Exenatide is a synthetic version of exendin-4, a peptide from the venom of the Gila monster that shares homology with human GLP-1 but resists rapid degradation. Approved in 2005, it was the first-in-class incretin mimetic and is available as a twice-daily injection (Byetta) and an extended-release once-weekly form (Bydureon).
It reduces HbA1c and produces modest weight loss, with gastrointestinal effects being the most common issue. While largely superseded by more potent weekly agents, exenatide has extensive clinical and post-marketing data, including the EXSCEL cardiovascular outcomes trial.
02 Mechanism
GLP-1 receptor agonist derived from exendin-4; enhances glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and promotes satiety.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Extended-release | 2 mg/wk | SubQ | Once-weekly depot (Bydureon). |
| Immediate-release | 5–10 mcg | SubQ | Twice-daily before meals (Byetta). |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Lowered blood glucose (HbA1c)Reduced HbA1c in type 2 diabetes trials. | ~0.8-1.5% HbA1c | Clinical | |
| Weight lossModest weight reduction. | ~2-3 kg | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Injection-site nodules (extended-release)Subcutaneous nodules at injection sites with the depot formulation. | Mild | Common | Clinical | |
| Nausea and GI upsetNausea and vomiting, particularly with the twice-daily form. | Moderate | Very common | Clinical | |
| Pancreatitis (rare)Rare acute pancreatitis reported. | Severe | Rare | Clinical |