About Byetta (exenatide)

Amylin Pharmaceuticals/ Eli Lilly & Co.
Incretins, such as glucagon-like peptide-1 (GLP-1), are hormones released from the gut in response to food intake. GLP-1 functions to control blood sugar levels by increasing insulin secretion from the pancreas, decreasing the release of glucagon (a hormone which controls the release of glucose from the liver after meals), promoting a feeling of fullness after eating a meal, and slowing the emptying of the stomach’s contents to allow more time for food absorption. GLP-1 is rapidly broken down in the body by the actions of dipeptidyl peptidase-4 (DPP-4). GLP-1 is deficient in individuals with diabetes.

Byetta belongs to a class of medications known as incretin mimetics. It is prescribed, in addition to diet and exercise, to improve glucose control in adults with type 2 diabetes. This type of medication improves blood sugar levels by copying the effects of naturally occurring GLP-1. The difference between Byetta and natural GLP-1 is that Byetta is resistant to breakdown by DPP-4. Therefore, Byetta injections allow individuals with type 2 diabetes to achieve high levels of GLP-1 for long periods of time, which in turn lowers blood glucose levels. Byetta may be used in combination with metformin, sulfonylureas, or thiazolidinediones.

Byetta lowers blood sugar levels in a glucose dependent manner. This means that Byetta increases insulin secretion from the pancreas only when glucose levels are high. This medication therefore is not likely to cause low blood sugar (hypoglycemia).

Byetta works by:
  • Signaling the pancreas to produce the correct amount of insulin after eating a meal.
  • Stopping the liver from producing unnecessary glucose after meals.
  • Reducing your appetite and the amount of food you eat, therefore promoting weight loss.
  • Slowing the rate at which food and glucose leave your stomach, therefore preventing high blood sugar levels after you eat.

Before Taking Byetta

Before taking Byetta, be sure to tell your doctor about all medications you are currently taking, including prescription and non-prescription medications, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or planning to become pregnant, or if you are breastfeeding.

Dosage and Forms

Byetta is a subcutaneous (under the skin) injection that is given twice daily; usually within 60 minutes before morning and evening meals, unless otherwise instructed by a physician. Byetta should not be administered after a meal. The initial dose of Byetta is 5mcg injected twice daily. After one month, the dose may be increased to 10mcg injected twice daily.

Byetta is supplied as 250mcg/mL exenatide in:
  1. 1.2mL prefilled pens (=60 doses at 5mcg twice daily)
  2. 2.4mL prefilled pens (=60 doses at 10mcg twice daily)
Proper Use of Byetta
  • Take Byetta exactly as prescribed for you by your physician
  • Check your blood sugar levels as directed by your doctor.
  • Stay on your prescribed diet and exercise program while taking Byetta
  • Talk to your doctor about how to prevent, recognize and manage low blood sugar (hypoglycemia), high blood sugar (hyperglycemia), and complications of diabetes while taking Byetta.
  • Do not take Byetta for a condition for which it was not prescribed.
Warnings and Precautions
  • Byetta is not indicated for use in patients with type 1 diabetes
  • Byetta should not be used as treatment for ketoacidosis (increased levels of ketones in the urine or blood).
  • Byetta is not insulin and should not be used as a substitute for insulin
  • The safety and efficacy of Byetta in individuals younger than 18 years of age has not been studied
Side Effects

Like all medications, Byetta may have unwanted side effects for some people. The most common of these include:
  • mild-to-moderate nausea (nausea was found to increase at higher doses, but in most cases subsides over time)
  • dizziness
  • diarrhea
  • vomiting
  • acid reflux
Although Byetta is associated with a low risk of hypoglycemia (low blood sugar), the use of Byetta in combination with sulfonylureas has been found to increase this risk. Make sure that you are aware of the signs and symptoms of hypoglycemia before taking this medication. These symptoms may include: headache, drowsiness, weakness, dizziness, confusion, irritability, hunger, fast heart beat, sweating, or feeling jittery.

Talk to your doctor if you are experiencing any of the above conditions, or any other bothersome side effects while using Byetta.


Active ingredients: exenatide

Inactive Ingredients: metacresol, mannitol, glacial acetic acid, and sodium acetate trihydrate in water for injection

Storage and Handling
  • Prior to first use, Byetta must be stored refrigerated at 2ºC to 8ºC (36ºF to 46ºF). After first use, Byetta can be kept at a temperature not to exceed 25ºC (77ºF).
  • Do not freeze Byetta Do not use Byetta if it has been frozen.
  • Keep Byetta protected from light.
  • Do not store Byetta pens with the needle attached. If the needle is left on, medicine may leak from the Byetta pen or air bubbles may form in the cartridge
  • The Byetta pen should be discarded 30 days after first use, even if some drug remains in the pen.
  • Byetta should not be used past the expiration date.