View the Table: GLP-1 and GIP/GLP-1 Receptor Agonists for Type 2 Diabetes

View the Table: GLP-1 and GIP/GLP-1 Receptor Agonists for Chronic Weight Management

The injectable glucagon-like peptide-1 (GLP-1) receptor agonist semaglutide (Wegovy) has been approved by the FDA to reduce the risk of major adverse cardiovascular events (MACE) in adults with established cardiovascular disease (CVD) and either obesity or overweight. Semaglutide is the first drug to be approved for cardiovascular risk reduction in this population. It is also approved in a lower-dose injectable formulation as Ozempic and in an oral formulation as Rybelsus (see Table 1).

The injectable glucose-dependent insulinotropic polypeptide (GIP)/glucagon-like peptide-1 (GLP-1) receptor agonist tirzepatide, which was approved by the FDA as Mounjaro for treatment of type 2 diabetes in 2022, has now been approved as Zepbound (Lilly) for chronic weight management in adults who have a BMI ≥30 kg/m² or a BMI ≥27 kg/m² and at least one weight-related comorbidity. The injectable GLP-1 receptor agonists liraglutide (Saxenda) and semaglutide (Wegovy) are approved for chronic weight management in patients ≥12 years old.

Glucagon-like peptide-1 (GLP-1) receptor agonists and the dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 receptor agonist tirzepatide (Mounjaro) are widely prescribed for treatment of type 2 diabetes and weight management (see Table 1), but they delay gastric emptying and commonly cause nausea and vomiting. Gastroparesis and bowel obstruction (ileus) have also been reported with their use.

Diet, exercise, and weight loss can improve glycemic control, but almost all patients with type 2 diabetes require antihyperglycemic drug therapy. Treating to a target A1C of <7% while minimizing hypoglycemia is recommended to prevent microvascular complications of diabetes (retinopathy, nephropathy, and neuropathy). An A1C target of <8% may be appropriate for some older patients.

The FDA has approved tirzepatide (Mounjaro – Lilly), a peptide hormone with activity at both glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, to improve glycemic control in adults with type 2 diabetes. Tirzepatide, which is injected subcutaneously once weekly, is the first dual GIP/GLP-1 receptor agonist to become available in the US. Selective GIP receptor agonists are not available in the US; GLP-1 receptor agonists have been available for years.

Adults with a body mass index (BMI) between 25 and 29.9 kg/m² are considered overweight. Those with a BMI ≥30 are considered obese. The initial recommendation for any weight loss effort is to achieve a 5-10% reduction in weight, which has been associated with a reduction in the risk of developing type 2 diabetes, hypertension, and dyslipidemia. Diet, exercise, and behavior modification are the preferred methods for losing weight, but long-term weight maintenance can be difficult. Several drugs and devices are FDA-approved for weight reduction and maintenance of weight loss.