Patients file lawsuits alleging GLP-1 drugs may raise risk of rare eye stroke

A group of consumers has filed lawsuits against Novo Nordisk, the maker of Ozempic and Wegovy, and Eli Lilly, the producer of Mounjaro and Zepbound, alleging that the GLP-1 receptor agonists may elevate the risk of nonarteritic anterior ischemic optic neuropathy (NAION), a rare eye stroke that can lead to permanent vision loss. The plaintiffs contend that the medications caused NAION, a condition in which blood flow to the optic nerve is abruptly reduced, resulting in sudden, painless loss of vision in one eye.

Dr. Douglas Lazzaro, an ophthalmologist at NYU Langone Health, said, "The problem with NAION is there's no treatment, so it can cause some very profound vision loss." He added that assessing statistical significance is difficult because of many variables, but noted that after adjusting for factors such as obesity, age, and hypertension, a higher risk of NAION was observed among users.

Novo Nordisk described the lawsuits as meritless and cited company-funded research that found no increased NAION risk. Eli Lilly said it continues to monitor safety data and that current studies do not demonstrate a causal link.

Observational studies published in JAMA Ophthalmology have reported a modest increase in NAION risk for semaglutide users compared with users of other diabetes drugs, and a Harvard Medical School study found a roughly four-fold higher relative risk, though the absolute risk remained low. Both studies emphasized that the findings are associative and do not prove causation.

The U.S. Food and Drug Administration is reviewing the evidence but has not issued a safety warning, while the European Medicines Agency has added NAION as a "very rare" adverse reaction to semaglutide product information.

Experts caution patients not to discontinue GLP-1 therapy without medical advice, noting that the drugs' benefits for diabetes and obesity may outweigh the potential, yet unconfirmed, vision risk.