FDA orders vision-loss warning on Ozempic, Wegovy and other GLP-1 drugs

The Food and Drug Administration said Monday that it is requiring the makers of every approved GLP-1 receptor agonist drug — including Novo Nordisk's Ozempic and Wegovy and Eli Lilly's Mounjaro and Zepbound — to add a new warning about a potential risk of sudden, sometimes permanent vision loss. The agency's safety communication cites a rare condition called non-arteritic anterior ischemic optic neuropathy, or NAION, which damages the optic nerve and typically causes abrupt, painless vision loss in one eye that cannot be reversed and has no approved treatment.

The requirement applies across the entire drug class: semaglutide products (Ozempic, Wegovy, Rybelsus), tirzepatide products (Mounjaro, Zepbound), and older GLP-1 medicines including Trulicity, Victoza, Saxenda, Byetta and Soliqua. The agency is ordering manufacturers to add the risk to the Warnings and Precautions section of their prescribing information, rather than to the more serious boxed-warning section that these drugs already carry for thyroid tumors seen in rodent studies.

What the evidence shows

The FDA said its decision rested on a pooled analysis of 126 randomized clinical trials covering more than 134,000 patients, in which it identified 15 probable NAION cases — 10 among people taking a GLP-1 drug and five among those on a placebo or a different medication. That worked out to an incidence rate of 6.4 cases per 100,000 patient-years among GLP-1 users, compared with 3.8 cases per 100,000 among the comparison group. Separate observational data, the agency said, showed a statistically significant increase in NAION risk for GLP-1 users compared with people taking DPP-4 inhibitors, though not compared with those on SGLT-2 inhibitors, and a review of animal studies found no biological mechanism to explain how the drugs might cause the damage.

The signal first drew attention from a 2024 single-center study at a Harvard-affiliated Boston eye hospital, published in JAMA Ophthalmology, which found a more than fourfold increase in NAION among diabetes patients prescribed semaglutide and a nearly eightfold increase among overweight or obese patients taking it, compared with matched patients on other drugs. A larger, multi-database study published the following year in the same journal found a smaller but still elevated association. Because diabetes, high blood pressure, sleep apnea, smoking, anemia and kidney disease — all common among people who take GLP-1 drugs — are themselves established NAION risk factors, researchers on both sides caution that none of the data proves the drugs directly cause the condition rather than simply appearing alongside it.

Who is affected, and what regulators elsewhere have already done

Tens of millions of Americans now take a GLP-1 drug for type 2 diabetes or obesity. The FDA's action brings the United States roughly in line with Europe, where regulators moved earlier: the European Medicines Agency's safety committee concluded in June 2025 that NAION should be listed as a "very rare" side effect of semaglutide, estimating it could affect up to 1 in 10,000 users, and the World Health Organization issued a global alert that same month urging prescribers to watch for the symptom and to stop treatment if it occurs. Those earlier actions covered semaglutide alone; the FDA's order this week is the first to apply across the whole GLP-1 class at once.

The FDA is advising patients to seek medical attention immediately for sudden vision loss in one eye — often first noticed on waking — along with blind spots, tunnel vision, color distortion or blurry central vision. Clinicians are told to refer suspected cases promptly to an ophthalmologist and to consider stopping the GLP-1 drug if NAION is confirmed, unless the benefits of continued treatment clearly outweigh the risk. The agency is asking doctors to report cases through its MedWatch system.

Company pushback and a parallel legal fight

Novo Nordisk and Eli Lilly do not dispute the labeling change but reject the idea that it proves their drugs cause the condition.

"Novo continues to believe the data do not establish a cause-and-effect relationship," a company spokesperson said, adding that Novo Nordisk remains confident in its medicines' overall benefit-risk profile.

Eli Lilly, for its part, noted that the FDA's communication applies to the entire drug class and does not cite findings specific to its own medicines, and said it is "carefully evaluating the update and will respond to FDA promptly," calling patient safety its "top priority."

The labeling order lands alongside an expanding product-liability fight already underway in federal court. Hundreds of lawsuits from patients who say a GLP-1 drug caused them to lose vision have been consolidated into a multidistrict litigation before a single judge in the Eastern District of Pennsylvania, where case-management orders covering discovery, a special master and plaintiff fact sheets have been issued roughly monthly through October. A parallel set of cases is proceeding in New Jersey state court. None of those claims has gone to trial, and the FDA's new warning does not resolve the underlying causation question at the heart of the litigation.

What happens next

Manufacturers must now update their labels to include the NAION warning; neither the FDA nor the companies have given a public deadline for when the revised labeling will reach pharmacy shelves. Analysts covering Novo Nordisk and Eli Lilly have generally characterized the risk as unlikely to change prescribing patterns given how rare NAION remains, and market reaction to the announcement was muted. The FDA has stressed it is not telling patients to stop taking their medication, only that they and their doctors should be aware of the symptom and act quickly if it appears. The litigation, meanwhile, is still in its early discovery phase, with the next scheduled case-management conference in the federal court likely to address how much of the scientific debate over causation will play out before any cases reach trial.