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Exploring FDA-approved GLP-1 receptor agonists
Glucagon-like peptide-1 (GLP-1) receptor agonists regulate blood sugar and aid weight loss, offering diverse applications beyond diabetes treatment.
Glucagon-like peptide-1 (GLP-1) receptor agonists, also called incretin mimetics, are a class of medications that mimic the effects of incretin hormones. These medications stimulate the body's GLP-1 receptors, which help regulate blood sugar levels and promote weight loss.
GLP-1 receptor agonists are primarily delivered via subcutaneous injections, such as liquid medication injected with a needle and syringe into the fatty tissue beneath the skin. These injections can be administered in different body regions, such as the abdomen, outer thighs, upper buttocks, and back of the arms.
As with any medication, GLP-1 receptor agonists carry potential side effects; however, specific GLP-1 receptor agonists may have varying side effect profiles. Common side effects include nausea, vomiting (particularly during the initial stages), diarrhea, headaches, and injection site reactions. Less frequently encountered side effects could involve hypoglycemia (in combination with certain medications), pancreatitis, gallbladder complications, and thyroid tumors.
Following FDA approval of the first GLP-1 receptor agonist in 2005, ongoing research is exploring potential applications and advantages of GLP-1 receptor agonists beyond their current prescribed uses.
FDA-Approved GLP-1 Receptor Agonists
In the United States, FDA-approved GLP-1 receptor agonist medications include the following:
- Exenatide
- Liraglutide
- Dulaglutide
- Semaglutide
A related class of medications, dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 receptor agonists, also exists. Only one such medication is available on the US market in two formulations: tirzepatide (Mounjaro, Zepound).
Exenatide (Byetta, Bydureon)
Exenatide is available in two different formulations: Byetta and Bydureon. Byetta is an immediate-release formulation, while Bydureon is an extended-release formulation. For easier administration, Bydureon is also available in pre-filled pen devices called Bydureon BCise.
Approval Date: Byetta (April 2005), Bydureon (January 2012).
Administration: Twice daily (Byetta), once weekly (Bydureon)
Manufacturer: Amylin Pharmaceuticals, Eli Lilly (Byetta); AstraZeneca (Bydureon)
Liraglutide (Victoza, Saxenda)
Victoza and Saxenda are brand-name injection pens that contain the same active drug, liraglutide. While they share the same active drug, they are approved for different uses.
Victoza is primarily used to treat T2D and lower the risk of heart problems in adults and children aged 10 years and older. When combined with improved diet and exercise, it helps manage blood sugar levels. Additionally, Victoza is approved to reduce the risk of major cardiovascular events, such as heart attack and stroke, in people with T2D and cardiovascular disease.
On the other hand, Saxenda is specifically approved for weight management in adults and children aged 12 years and older who are obese or overweight and have weight-related medical problems. It is combined with a healthy diet and exercise to help with long-term weight loss and maintain weight loss once achieved.
Both Victoza and Saxenda are self-injected once daily using a prefilled pen. However, the dosages for Victoza and Saxenda differ. Victoza can be given in dosages of 0.6, 1.2, or 1.8 mg once per day, depending on the treatment plan prescribed by the doctor. Saxenda, used for weight management, is administered in a higher dosage of 3 mg once per day, with the dosage gradually increasing over the first 5 weeks of treatment.
Approval Date: Victoza (January 2010), Saxenda (December 2014)
Administration: Once daily
Manufacturer: Novo Nordisk
Dulaglutide (Trulicity)
Trulicity is an injectable medication to help control blood sugar levels in adults with T2D mellitus. It is typically used with diet and exercise to improve blood sugar control. Trulicity is also prescribed to reduce the risk of serious heart problems, such as heart attack or stroke, in adults who have T2D and heart disease. However, it is important to note that Trulicity is not approved for treating type 1 diabetes.
Approval Date: September 2014
Administration: Once weekly
Manufacturer: Eli Lilly
Semaglutide (Ozempic, Rybelsus, Wegovy)
Ozempic has been approved to lower blood sugar levels in people with T2D, alongside diet and exercise, and serves as a preventative measure against major cardiovascular events in diabetic patients with existing cardiovascular disease. Similarly, Wegovy facilitates weight loss and mitigates the risk of heart attack, stroke, and cardiovascular death in overweight or obese adults with cardiovascular disease, complemented by a reduced-calorie diet and increased physical activity. Conversely, Rybelsus, available as an oral tablet, lowers blood sugar levels in patients with T2D.
Approval Date: Ozempic (December 2017), Rybelsus (September 2019), Wegovy (June 2021)
Administration: Once weekly (Ozempic, Wegovy); daily oral tablet (Rybelsus)
Manufacturer: Novo Nordisk
Tirzepatide (Mounjaro, Zepound)
Mounjaro and Zepbound are two medications that contain the same active ingredient, tirzepatide. They are used to treat specific health conditions, but their approved uses differ.
The FDA has approved Mounjaro for the treatment of T2D, which is used in tandem with diet and exercise to improve glycemic control in adults. Mounjaro helps lower blood sugar levels by activating GIP/GLP-1 receptors. It also aids insulin release from the pancreas and helps regulate appetite.
Zepbound has been FDA-approved for weight management. It is indicated for obese adults or overweight individuals with weight-related health issues such as hypertension, high cholesterol, or T2D. Zepbound works similarly to Mounjaro, activating GIP/GLP-1 receptors to regulate blood sugar levels and control appetite.
Mounjaro and Zepbound are administered subcutaneously once a week and have the same dosing strengths. They may cause similar side effects, such as gastrointestinal discomfort, but these are usually mild and temporary.
Approval Date: Mounjaro (May 2022), Zepound (November 2023)
Administration: Once weekly
Manufacturer: Eli Lilly
GLP-1 receptor agonists represent a significant advancement in the management of T2D and obesity-related conditions. By mimicking the effects of incretin hormones, these medications offer patients a multifaceted approach to improving their health outcomes. Despite the potential for side effects, the overall efficacy and safety profile of GLP-1 receptor agonists has made them a cornerstone in modern diabetes and obesity management. Ongoing research continues to explore the expanding applications and advantages of these medications, paving the way for further innovations in the treatment of metabolic disorders.
