The science of safety: adverse effects of GLP-1 receptor agonists as glucose-lowering and obesity medications

GLP-1 receptor agonist (GLP-1RA) medications have transformed the treatment of type 2 diabetes (T2D) and obesity, with robust evidence for cardiovascular and renal benefits. Nevertheless, GLP-1RA therapy is associated with a pattern of adverse events affecting their safety and tolerability. Here, we delineate mechanisms potentially leading to adverse responses to GLP-1RAs, describe the impact of side effects on treatment persistence, discuss potential mitigation strategies, and identify areas requiring further studies. Concerns that GLP-1RAs raise the risk for acute pancreatitis and pancreatic cancer have been dispelled by long-term clinical trials. However, GLP-1RAs may confer an increased risk for thyroid cancer. Sight-threatening eye complications resulting from rapid reductions in glycemia may be avoided by retinal screening and ophthalmologic treatment before GLP-1RA initiation. The slowing of gastric emptying with GLP-1RA treatment increases the propensity for retained gastric contents, which could increase the risk of aspiration during upper gastrointestinal endoscopy or general anesthesia. These risks may, however, be elevated in individuals with long-standing T2D even in the absence of GLP-1RA treatment. Improved pharmacovigilance and a more standardized, quantitative assessment of adverse events in clinical trials, particularly in the assessment of gastrointestinal symptoms, would facilitate definition of the benefit-risk relationship for individual medications and indications.