GLP-1 diabetes drugs linked to rare eye-stroke condition amid growing lawsuits

Hundreds of plaintiffs have filed lawsuits claiming that GLP-1 drugs, including Novo Nordisk’s semaglutide products and Eli Lilly’s tirzepatide, raise the likelihood of non-arteritic anterior ischemic optic neuropathy (NAION), a rare condition that abruptly reduces blood flow to the optic nerve and can cause permanent vision loss. Researchers analyzing 37 million adults reported a modest increase in NAION risk for semaglutide users compared with SGLT2-inhibitor users, and a Harvard study observed about a fourfold higher relative risk, though the overall incidence stays very low and the studies are observational.

The FDA is currently reviewing the evidence, while the European Medicines Agency has added NAION as a “very rare” adverse reaction to semaglutide labeling. Novo Nordisk called the suits meritless and pointed to company-funded studies showing no link; Eli Lilly said safety data are being monitored and existing studies do not prove causation. Ophthalmologist Douglas Lazzaro notes that patients with a “disc at risk” may be advised against semaglutide, but for most, the drugs’ health benefits likely outweigh the small potential eye-stroke risk.