Pharmacology · GLP-1 receptor agonists
Exenatide !
The first GLP-1 agonist: a synthetic copy of exendin-4, a peptide from Gila monster saliva. Injected twice a day, or weekly as a slow-release form.
Updated 2026-11-01
The figure shows exendin-4 (the natural peptide whose synthetic form is exenatide) bound to the human GLP-1 receptor with its Gs protein.
Mechanism of action
Exenatide is synthetic exendin-4, a reptile peptide that shares about half of its sequence with human GLP-1 and is not cut by DPP-4. It activates the GLP-1 receptor: glucose-dependent insulin release rises, glucagon falls after meals, the stomach empties more slowly and appetite falls.
- Activates the GLP-1 receptor (Gs, cAMP)
- Beta cells release more insulin when glucose is high
- Glucagon falls and the stomach empties more slowly
- Appetite falls: lower glucose and weight
Pharmacokinetics
- Absorption
- Subcutaneous injection; the short form is given before meals, the extended-release form weekly.
- Elimination
- Mainly by the kidney (filtration and breakdown), so it is avoided in severe kidney failure.
Indications
- Type 2 diabetes, with diet and exercise, alone or combined Type 2 diabetes mellitus →
Adverse effects
Common
- Nausea, vomiting, diarrhea, constipation, abdominal pain (most common, mostly at the start)
- Reduced appetite
- Injection-site reactions
- Slightly faster heart rate
Contraindications
- Severe kidney failure
- Serious hypersensitivity to exenatide
- Medullary thyroid carcinoma or MEN 2 (GLP-1 class caution)
Key interactions
- Insulin or sulfonylureas
- Higher risk of hypoglycemia; their dose is often reduced.
- Oral drugs in general
- Slower gastric emptying can change their absorption.
- Oral contraceptives and antibiotics
- Usually taken well before the injection, so slowed gastric emptying does not reduce their absorption.
What is monitored
- HbA1c and weight
- Kidney function
- Symptoms of pancreatitis
Administration and safety
- Subcutaneous injection in the abdomen, thigh or upper arm, rotating sites.
- Pens are for one person only and are never shared, even with a new needle.
- The short-acting form is injected before meals, not after them.
- Unopened pens are kept in the refrigerator, not frozen.
Nursing care
- Before: thyroid history (medullary carcinoma, MEN 2), pancreatitis history, kidney function.
- During: severe abdominal pain spreading to the back (pancreatitis), vomiting and dehydration.
- Teach to report a neck lump, hoarseness or trouble swallowing.
- The anesthesia team is told before surgery or endoscopy.
Pregnancy and breastfeeding
Not used in pregnancy (weight loss is not a goal and animal data showed harm); it is stopped ahead of a planned pregnancy.
Test yourself
Think of the answer, then tap the question to see it.
Where does exenatide come from?
It is a synthetic copy of exendin-4, a peptide found in the saliva of the Gila monster (Heloderma suspectum).
Why is exenatide avoided in severe kidney failure?
It is cleared mainly by the kidney, so it accumulates and side effects increase.
Why is exenatide not broken down by DPP-4?
Its sequence differs from GLP-1 at the N-terminal cutting site, so the enzyme cannot inactivate it.
Related drugs
Related conditions
← Back to the class: GLP-1 receptor agonists
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Exenatide Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Exendin-4-bound Glucagon-Like Peptide-1 (GLP-1) Receptor in complex with Gs protein (RCSB Protein Data Bank, 2022); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 51 (McGraw Hill, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.