Byetta | exenatide

Medication Class: Glucagon-like peptide-1 (GLP-1) receptor agonist
Manufactured By: Bristol Myers Squibb
Approval Date: May 2005

What is Byetta and how does it work

Byetta belongs to a group of drugs known as glucagon-like peptide-1 (GLP-1) receptor agonists because they resemble and mimic the action of human GLP-1 hormone (incretin hormone). They are also known as incretin mimetics. It is an injectable drug that reduces blood glucose by increasing insulin production by the pancreas, slows the absorption of glucose from the gut, reduces the activity of glucagon (a hormone that increases release of glucose from the liver), and reduces appetite.

What does Byetta treat

• Type 2 diabetes mellitus in conjunction with diet and exercise. It is not used for treating type-1 diabetes or diabetic ketoacidosis and it should not be used in place of insulin when patients require insulin.

How effective is Byetta

• Monotherapy: Byetta 5 to 10 mcg injected before and after meals in the morning and evening over 24 weeks significantly reduced HbA1c from baseline better than placebo. The average reductions in HbA1c were -0.2% for placebo, -0.7% for Byetta 5 mcg, and -0.9% for Byetta 10 mcg.

• Combination therapy: Byetta 5 to 10 mcg twice daily in combination with other anti-diabetic agents (metformin, sulfonylurea, pioglitazone, or rosiglitazone) reduced HbA1c from baseline better than placebo after 30 or 16 weeks of treatment. Changes in HbA1c were -0.0% for placebo, -0.5% for Byetta 5 mcg/metformin, and -0.9% for Byetta 10 mcg/metformin; +0.1% for placebo, -0.5% for Byetta 5 mcg/sulfonylurea, -0.9% for Byetta 10 mcg/sulfonylurea; +0.1% for placebo and -0.7% for Byetta 10 mcg/pioglitazone or rosiglitazone.
• Byetta versus Victoza: In one 26-week study Victoza 1.8 mg daily reduced HbA1c more than Byetta 10 mg twice daily (-1.12% versus -0.79%) and more patients treated with Victoza achieved HbA1c below 7%. Average reduction in weight was similar between both drugs (-3.24 kg versus -2.87 kg).

What are interesting facts about Byetta

• First FDA approved incretin mimetic.
• Patients can develop antibodies which may reduce the effect of Byetta.
• Byetta may reduce appetite and cause weight loss.
• There is a once-weekly extended-release formulation of exenatide called Bydureon.

What are the side effects of Byetta

Common: nausea, vomiting, diarrhea, nervousness, dizziness, increased sweating, headache, acid reflux, reduced appetite, stomach discomfort, and injection site reactions. The risk of hypoglycemia (low blood glucose) is increased when combined with a sulfonylurea.

What is the dosing of Byetta 

BYETTA pen is available as pre-filled multiple dose pen:

• 300 mcg/1.2 mL
• 600 mcg/2.4 mL

The initial recommended dosage of Byetta pen is 5 mcg injected under skin (thigh, abdomen, or upper arm) twice daily 60 minutes before breakfast and dinner. After 1 month, the dosage can be increased to Byetta 10 mcg twice daily.

Byetta drug interactions

• Warfarin (Coumadin, Jantoven): Byetta may increase the effect of warfarin, leading to more bleeding.
• Byetta slows movement of food and drugs through the intestines and therefore can reduce the absorption of oral drugs. Oral medications should be administered one hour before injecting Byetta.

What is the price of Byetta

Byetta costs $200 to $300 per pen.

How to obtain prescription cost assistance for Byetta

For prescription assistance visit:

MySavingsRx Card

BMS Patient Assistance Program

Reference: Byetta FDA Prescribing Information and medication Guide.