GLP 1 NAION lawsuits move ahead as vision loss evidence stays split

GLP 1 NAION lawsuits against Eli Lilly and Novo Nordisk now sit in federal court in Philadelphia, a MedShadow report published on 28 October 2026 shows. Plaintiffs say the companies failed to warn that their drugs could cause sudden vision loss, while doctors quoted in the report say the science on cause is still unsettled. Regulators abroad have already acted on the eye risk. The United States label, according to the report, still does not name it.

What the GLP 1 NAION lawsuits claim

The core claim is about warnings. According to MedShadow, the complaints allege that Eli Lilly and Novo Nordisk knew, or should have known, about a possible higher risk of nonarteritic anterior ischemic optic neuropathy, known as NAION, and did not tell patients or prescribers. Novo Nordisk makes Ozempic and Wegovy, and Lilly makes Mounjaro. NAION causes sudden loss of sight, often permanent and usually in one eye, when blood flow to part of the optic nerve drops. MedShadow reports that the United States prescribing information for these drugs lists several serious risks but carries no specific NAION warning. That gap is the heart of the failure to warn theory. The companies have not conceded any link, and no court has ruled on whether the drugs cause the condition.

The federal cases are grouped in two multidistrict litigation dockets in the U.S. District Court for the Eastern District of Pennsylvania, the report says. One covers gastrointestinal injury and pancreatitis. The other covers vision loss and is listed by the court as MDL 3163. A multidistrict litigation pools similar suits before one judge for shared evidence and pretrial rulings, but each claim still has to be proven on its own. In a statement to MedShadow, Lilly said patient safety is its "top priority" and that it reports safety information for its medicines to the FDA. The company said it has ongoing talks with regulators on possible safety topics, including eye and gut issues. Novo Nordisk did not respond to a request for comment, MedShadow reported.

Semaglutide NAION risk in the research

The evidence on semaglutide NAION risk points in different directions. A 2024 study in JAMA Ophthalmology from Massachusetts Eye and Ear reviewed records of 16,827 patients seen by neuro ophthalmologists at one academic center. Among people with type 2 diabetes, it counted 17 NAION events in those prescribed semaglutide against 6 in those on other diabetes drugs, and its model gave a hazard ratio of 4.28. The authors wrote that the study was observational, so it could not prove the drug caused the eye damage. The American Academy of Ophthalmology and the North American Neuro Ophthalmology Society said in a joint statement that "this is not the type of study that can show the treatment caused NAION." They did not advise patients to stop their medicine.

A larger 2025 study of more than 370,000 adults with type 2 diabetes found no statistically significant difference in NAION risk with GLP 1 drugs.

A larger 2025 study of more than 370,000 adults with type 2 diabetes found no statistically significant difference in NAION risk with GLP 1 drugs. The study in JAMA Network Open used the TriNetX records network and matched 185,066 users with the same number of nonusers. Its NAION hazard ratio was 1.26, with a confidence interval that crossed 1. The same paper did find a modest rise in diabetic retinopathy among users. Nate Wood, a Yale School of Medicine physician quoted by MedShadow, said, "we still don't know if it actually increases the risk, really." He said weight change, blood pressure, hydration or nutrition linked to treatment could also play a part. Some people have a narrow opening where the optic nerve leaves the eye, which may raise their risk.

EMA very rare side effect ruling and other regulators

Europe moved first. In June 2025, the European Medicines Agency's safety committee, PRAC, concluded that NAION is a very rare side effect of semaglutide, the drug in Ozempic, Rybelsus and Wegovy. The EMA safety committee said the condition may affect up to 1 in 10,000 people taking the drug. It based that on clinical trials, post marketing reports, the medical literature and several large epidemiological studies. Those studies suggested about a twofold rise in risk for adults with type 2 diabetes, or roughly one extra case per 10,000 person years of treatment. The agency advised patients with sudden or fast worsening vision loss to contact a doctor without delay, and said treatment should stop if NAION is confirmed.

Other agencies followed. MedShadow reports that regulators in the United Kingdom, the European Union, Australia and Japan have recommended label updates that warn of a possible link, despite the mixed findings. Our earlier report on the EU eye condition warning covered the PRAC decision when it was issued. In the United States, the report says, the prescribing information does not yet name NAION. That difference matters for the GLP 1 NAION lawsuits, because failure to warn claims turn on what a company knew and what its label told doctors. A label change abroad does not prove the drug causes the condition. It shows that regulators judged the signal strong enough to tell patients. The table below sets out the main studies and decisions cited in the coverage.

GLP 1 pancreatitis risk and gut injury claims

The second docket rests on weaker ground for plaintiffs on the warning question. MedShadow notes that pancreatitis and gastrointestinal injury already appear in the prescribing information of these drugs. Dr. Wood told the outlet the chance of pancreatitis from a GLP 1 drug is extremely small. The data on GLP 1 pancreatitis risk are mixed. A September 2025 meta analysis in Endocrinology, Diabetes and Metabolism pooled 62 randomised trials with 66,232 patients and found a 44 percent higher relative risk of pancreatitis with these drugs. When the authors split patients by whether they took other background medicines, the link was no longer statistically significant. Gut side effects such as nausea are common, and doses are raised slowly in part to lower the chance of bowel obstruction or stalled stomach emptying.

Use is now wide. A Gallup survey run in May and June found that about 11 percent of U.S. adults take a GLP 1 drug for weight loss, and about 15 percent have used one at some point, MedShadow reported. Many get care from a doctor who adjusts treatment slowly. Others use telehealth sellers or compounding pharmacies, which face lighter oversight than drug makers, the report said. Recent cases such as a compounded tirzepatide sterility recall show how that channel can carry its own risks. Dr. Wood warned that some for profit online services may raise doses quickly to speed weight loss, which he said could add risk. Anyone with sudden vision change while on these drugs should seek prompt medical care. This report is not medical advice.

Conclusion

The GLP 1 NAION lawsuits test a question the science has not settled: whether the drugs cause a rare form of vision loss or only travel with it. Europe has labelled NAION a very rare side effect, while one large American study found no clear rise in risk. Pretrial proceedings in Philadelphia are where that evidence will be tested. Patients who notice sudden sight loss should contact a doctor quickly, and no one should stop a prescribed medicine without medical advice.