GLP-1 Drugs Face Mounting NAION Lawsuits as Regulators Split on Vision-Loss Warnings
核心洞察
More than 90 lawsuits have been filed in New Jersey state court against Novo Nordisk on behalf of patients who developed NAION after taking Ozempic or Wegovy.
The European Medicines Agency (搜索) concluded in June 2025 that NAION is a very rare side effect of semaglutide, while the FDA continues investigating without requiring a US label warning.
Denmark has paid more than $1.5 million to 27 patients who developed vision loss (搜索) after Ozempic or Wegovy, with 38 additional cases still under review.
Patients in the United States who developed sudden, often permanent vision loss (搜索) after treatment with glucagon-like peptide-1 (GLP-1) receptor agonists are pursuing lawsuits against the drugs' manufacturers, while regulators in Europe, Britain, Japan and Australia have added label warnings that the US Food and Drug Administration (搜索) has so far declined to require.
The claims center on non-arteritic anterior ischemic optic neuropathy (搜索) (NAION), a condition in which blood flow to the optic nerve decreases, causing sudden vision loss (搜索) that is frequently permanent. The Wall Street Journal reported the case of Michelle Fennell, a 53-year-old US resident who felt heaviness in her right eye while at her desk and then experienced blurred vision. She could see straight ahead but not to the right or below. Two weeks later she was diagnosed with NAION, and her physician told her to stop taking Ozempic immediately to preserve her remaining sight. She had started the drug about six months earlier to treat type 2 diabetes (搜索).
Litigation Against Novo Nordisk and Eli Lilly
Fennell is one of dozens of people who have sued Novo Nordisk, maker of Ozempic and Wegovy, arguing the drug caused the side effect. A similar number of suits have been filed against Eli Lilly, maker of Zepbound. The US personal injury firm Weitz & Luxenberg (搜索) has filed more than 90 lawsuits in New Jersey state court since last year on behalf of patients who developed NAION while taking Ozempic or Wegovy. Separate suits filed around the same time in federal court in Philadelphia claim that the two companies' GLP-1 drugs caused vision loss (搜索) and that the companies failed to adequately warn patients.
Both companies are contesting the suits, saying there is not enough evidence to support the claim that their drugs are responsible.
Divergent Regulatory Positions
The European Medicines Agency (搜索) concluded in June 2025 that NAION is a very rare side effect of semaglutide, the active ingredient in Ozempic and Wegovy, and recommended adding a warning to European product information for Novo Nordisk's drugs. Britain, Japan and Australia also carry related warnings or risk information on their labels. In Australia and New Zealand, the information has been included on labels of other GLP-1 drugs as well, including Eli Lilly's Mounjaro, which uses the compound tirzepatide, as does Zepbound.
The United States has no such warning. The FDA has been investigating a potential link since it first identified the possible connection to NAION in late 2024. Aaron Kesselheim, a Harvard Medical School professor who studies FDA regulation, said the agency "is fairly conservative about what warnings it puts on a label," adding that it is assessing the evidence on whether the drugs actually cause the side effect.
Conflicting Evidence on Risk
Research indicates that when NAION develops in GLP-1 users, it most often appears within six to 18 months of starting treatment. Some studies found the risk of NAION may be about twice as high in patients taking semaglutide compared with those who did not, while a study by an ophthalmology institute found the risk could increase by nearly eight times. Because NAION is itself very rare, on average only about two out of every 10,000 people taking the medication are estimated to develop it. A large-scale study supported by Novo Nordisk did not provide evidence that GLP-1 medicines increase NAION risk.
The discrepancies have been attributed to differences in how NAION is classified across studies, and to the fact that many GLP-1 users already have conditions that are themselves risk factors for NAION, including diabetes, cardiovascular disease, high blood pressure and sleep apnea. Doctors and researchers said the evidence is mixed and not clear enough to determine whether the drugs cause the condition, or how. NAION usually affects one eye but sometimes both, and there is no approved treatment.
Compensation in Denmark
In Denmark, where Novo Nordisk is headquartered, more than $1.5 million in compensation has been paid to 27 patients who developed vision loss (搜索) after taking Ozempic or Wegovy, and another 38 cases are under review, according to the Danish Patient Compensation Association (搜索), an independent body that assesses medical claims. The awards are part of a government program that compensates patients for rare and serious adverse drug effects, with decisions made by the independent board and no involvement from Novo Nordisk. Dr. Tine Bilsboell of Novo Nordisk said the payments are not an indicator of a causal relationship.
Clinical Guidance for Prescribers
The American Optometric Association recommended last year that anyone beginning a GLP-1 drug undergo an eye examination to check the health of the optic nerve.
Dr. John Chen, a professor at the Mayo Clinic who specializes in optic nerve disorders, said doctors should help patients weigh the risks and benefits themselves. For patients who need the drugs to control diabetes or heart disease, the benefits are likely to outweigh the risks, he said. The calculation differs for someone who simply wants to lose a small amount of weight. "If you want to lose five pounds, it's not worth that kind of risk," Chen said.