What it is
Exenatide was the first GLP-1 receptor agonist approved in the US. It is based on exendin-4, a peptide first found in Gila monster venom.
Like other drugs in its class, it helps the pancreas release insulin when blood sugar is high, lowers glucagon, and slows stomach emptying. Byetta was a twice-daily injection and Bydureon BCise was a weekly extended-release version.
US regulatory status
FDA-approved for type 2 diabetes, but AstraZeneca discontinued the Byetta and Bydureon BCise brands in October 2024 for business reasons. A generic exenatide injection (equivalent to Byetta) was approved by the FDA in November 2024, so availability depends on the pharmacy.
What the research shows
Exenatide has many years of clinical trial and real-world data showing lower A1C and modest weight loss in type 2 diabetes. The EXSCEL trial of weekly exenatide found it was safe for the heart but did not show a statistically significant reduction in major cardiovascular events. It has also been studied in Parkinson's disease, where a large 2025 trial did not show benefit.
How it is given
Subcutaneous injection (pen)
Commonly reported side effects
- Nausea
- Vomiting
- Diarrhea
- Feeling jittery
- Dizziness and headache
- Injection site bumps (weekly version)
Questions to ask your provider
- Is exenatide still available at my pharmacy, or should I switch to a different option?
- How would switching from exenatide to another GLP-1 medicine work for me?
- What should I do about low blood sugar if I also take a sulfonylurea or insulin?