The U.S. Food and Drug Administration is requiring manufacturers of popular diabetes and weight loss drugs, including Ozempic and Wegovy, to add warnings about a rare eye condition that can cause permanent vision loss. The agency announced the decision on Monday, stating that the risk must be printed on the labelling of all medications in the GLP-1 receptor agonist class. TonyBet offers dozens, with some games boasting pots in the multimillions . The condition, non-arteritic anterior ischemic optic neuropathy (NAION), results from decreased blood flow to the optic nerve and can cause significant, irreversible vision loss. The FDA said the underlying cause of the condition is unknown.
The labelling requirement stems from a review of more than 125 clinical trials and adverse event reports. An FDA analysis found NAION occurred in roughly six of every 100,000 patients who took a GLP-1 drug for at least one year. The comparable rate for people taking a placebo or other glucose-lowering medications was less than four per 100,000. "Based on these findings, FDA is requiring that application holders add information about the risk for NAION to the Warnings and Precautions section of labelling of all GLP-1 RAs," the agency stated. Symptoms of NAION include sudden, painless vision loss, blurred vision, blind spots, distorted colours and other visual irregularities, according to the regulator. The FDA advises anyone experiencing sudden vision loss, particularly in one eye, to contact a health care professional immediately. The agency has not advised all patients to stop taking their medication but recommends discussing individual risks with prescribing doctors.
The warning covers all medications in the FDA's GLP-1 category, which are used to treat obesity, diabetes and other conditions. This includes injectable and pill-based drugs such as Novo Nordisk's Ozempic, Wegovy and Rybelsus, which contain semaglutide. It also includes Eli Lilly's Mounjaro and Zepbound, which contain tirzepatide. The FDA began investigating the potential connection after a 2024 study raised concerns about NAION among patients prescribed semaglutide.
The agency's review included clinical trials, animal studies and research using real-world medical records. In an analysis of 126 clinical trials involving over 134,000 participants, researchers identified 15 probable NAION cases. Ten were among GLP-1 users and five were among participants in comparison groups. The incidence rate was 6.4 cases per 100,000 person-years among GLP-1 users, compared with 3.8 among the comparison groups. The FDA also examined medical records from adults with type 2 diabetes but found no statistically significant increase in NAION risk compared with one class of other diabetes drugs.
The findings point to a possible association but do not establish that the medications directly cause NAION. The FDA acknowledged that further questions about the relationship remain. The absolute risk remains very small, with the difference amounting to roughly two to three additional cases for every 100,000 people followed for a year. Risk factors for NAION include diabetes, high blood pressure, smoking, sleep apnea, anemia and kidney disease, several of which are common among people prescribed GLP-1 drugs.
Last month, Health Canada announced it had identified a potential safety risk related to Ozempic, Rybelsus and Wegovy, citing NAION as the health issue under review. The findings of that review have not yet been published. Canada operates under its own regulatory framework for labelling standards. Other studies published this year have linked GLP-1 use to outcomes such as reducing the risk of developing cancer. A separate observational study found GLP-1 usage was associated with a higher risk of hair loss, though absolute rates were low.