Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are injectable medications that treat type 2 diabetes.
Similar to insulin, they’re injected under the skin. GLP-1 RAs are most commonly used jointly with other antidiabetic treatments.
Currently, there are several GLP-1 RAs on the market that differ by dosing schedule and duration of action. They include:
- exenatide (Byetta)
- dulaglutide (Trulicity)
- semaglutide (Ozempic, Wegovy) — also available in tablet form (Rybelsus)
- liraglutide (Saxenda, Victoza)
- lixisenatide (Adlyxin)
- pramlintide (Symlinpen)
- tirzepatide (Mounjaro)
In 2022, the
Pramlintide (Symlin) is another injectable drug approved for the treatment of type 2 diabetes. It’s used in conjunction with mealtime insulin shots. Though less commonly used, it works similarly to GLP-1 RAs.
These drugs can help delay gastric emptying, increase feelings of fullness (satiety), lower cholesterol, and lower both systolic and diastolic blood pressure.
Unlike insulin and other antidiabetic drugs, injectables do not cause weight gain.
Because they decrease appetite, they may even contribute to weight loss in the range of
- use of other medications
Because of this, GLP-1 RAs are well suited for people who are overweight or have obesity. They’re often used in combination with other drugs or insulin to reduce the chance of (mitigate) weight gain.
GLP-1 RAs are available in prefilled pens that you administer yourself, similarly to administering insulin. They differ by dosage and duration of action.
There are currently no comparative trials that show how the choice of medication affects long-term patient outcomes.
A doctor will usually start you off with a low dosage. This will be gradually increased according to tolerance and desired effect.
Exenatide (Byetta) is the only agent that needs to be administered twice a day. The others are daily or weekly injections.
Gastrointestinal side effects, such as nausea, vomiting, and diarrhea, occur in many patients. Nausea may lessen over time or by lowering the dose. It may also occur less frequently with weekly agents.
Other side effects may include:
- mild tachycardia or an increased heart rate
Some reports link acute pancreatitis with GLP-1 RAs, but there’s not enough data to establish a clear causal relationship.
Some GLP-1 RAs may cause local skin reactions at the injection site. Some people using exenatide (Bydureon, Byetta) have reported this side effect.
Hypoglycemia rarely occurs with GLP-1 RAs when used alone. However, adding them to insulin-based therapies can increase risk.
In rodent studies, there was an increase in medullary thyroid tumors. A similar effect has not yet been found in humans.
Doctors recommend that people who may become pregnant use contraceptives while taking this medication.
People can develop allergies to GLP-1 RAs. Signs of a life threatening allergic reaction can include:
- trouble breathing
- facial swelling
- losing consciousness
- feeling lightheaded
If you experience the above signs of anaphylaxis after taking medication, call 911 or your local emergency services.
Lifestyle changes for people with type 2 diabetes may consist of:
- modifying diet
- losing 5 to 10 percent of body weight, for those who have overweight or obesity
- regularly exercising for 150 minutes a week
- self-monitoring of blood sugars
- limiting alcohol to one drink per day for adult women and two drinks per day for adult men
- not smoking or quitting smoking if you currently smoke
The diabetes plate method is commonly used for providing basic meal planning guidance and for its visual help.
Seeing a registered dietitian may also help lead you to a healthier diet. A dietitian can recommend an individualized nutrition plan that accounts for your specific factors and preferences.
In general, reducing your carbohydrate intake is necessary to improve blood sugar management.
Choose carbs that are:
- high in fiber
- minimally processed
Replace sugar-sweetened beverages with water.
Additionally, eating foods rich in monounsaturated and polyunsaturated fats might improve glucose metabolism and lower cardiovascular risk.
Injectable GLP-1 RAs and pramlintide (Symlin) are expensive. No generic options are currently available.
The price of these medications can vary by pharmacy and by insurance. The prices included in this list are estimates and may not correspond to the price you receive at an individual pharmacy.
According to GoodRx, average prices are as follows:
- exenatide (Byetta): $954
- dulaglutide (Trulicity): $949
- semaglutide (Ozempic): $1044
- semaglutide (Wegovy): $1,936
- semaglutide (Rybelsus): $1058
- liraglutide (Saxenda): $1,630
- liraglutide (Victoza): $1078
- lixisenatide (Adlyxin): $702
- pramlintide (Symlinpen): $1,140
- tirzepatide (Mounjaro): $486 to $511
These are covered by many insurance plans. but policy guidelines, exclusions, requirements for step therapy, and prior authorization vary widely.
It can be helpful to become familiar with the specifics of your prescription drug plan.
Injectable medications like glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are used to treat type 2 diabetes. Most of these drugs are given daily or weekly and administered by the person using them.
Like other medications, they may cause side effects, including nausea and diarrhea.
In addition to medication, a doctor may also recommend lifestyle changes such as following a specific diet and adhering to an exercise plan to treat type 2 diabetes.
Dr. Maria S. Prelipcean is a physician specializing in endocrinology and diabetes. She currently works at Southview Medical Group in Birmingham, Alabama. Dr. Prelipcean is a graduate of Carol Davila Medical School in Bucharest, Romania. She completed her internal medicine training at the University of Illinois and Northwestern University in Chicago and her endocrinology training at the University of Alabama in Birmingham. Dr. Prelipcean has been repeatedly named as a Birmingham Top Doctor and is a Fellow of the American College of Endocrinology. In her spare time, she enjoys reading, traveling, and spending time with her family.