FDA warns GLP-1 drugs may pose risk of rare condition that causes vision loss

The FDA is requiring makers of GLP-1 drugs including Ozempic, Wegovy, Zepbound, and Mounjaro to add warnings about a potential link to NAION, a rare eye condition caused by restricted blood flow to the optic nerve that can result in permanent vision loss.

The agency announced the labeling requirement Monday following a review of clinical trial data and medical records. In its own meta-analysis of 126 trials covering over 130,000 patients, the FDA identified 15 probable NAION cases: 10 in GLP-1 users, five in placebo recipients, and none in patients on non-GLP-1 drugs. A separate retrospective study of type 2 diabetes patients found increased NAION risk in GLP-1 users compared to those taking DPP-4 inhibitors, but not compared to those on SGLT-2 inhibitors.

The first study linking GLP-1 drugs to NAION came in 2024 from Harvard University researchers published in JAMA Ophthalmology. Among diabetes patients taking semaglutide after 36 months, 8.9 percent developed NAION versus 1.8 percent in non-GLP-1 groups. In overweight or obese patients, 6.7 percent on GLP-1 developed the condition compared to 0.8 percent in control groups. The study faced criticism for potential selection bias and lack of generalizability, as patients came from a single referral center treating most of the region's NAION cases.

Subsequent research produced mixed results. A meta-analysis of 78 randomized controlled trials found semaglutide increased NAION risk but not general eye disorders, though the finding relied on just five trials reporting NAION events. An electronic health records study of 37.1 million diabetic patients found no general link between semaglutide and NAION.

NAION affects two to 10 people per 100,000 in the general population. The European Medicines Agency estimated it may affect up to one in 10,000 people taking semaglutide.

The FDA advises healthcare providers to "consider discontinuing the GLP-1 RA in patients who develop NAION, unless the benefits of treatment clearly outweigh the risk." The American Academy of Ophthalmology and North American Neuro-Ophthalmology Society recommend shared decision-making between patients and care teams, stating causation remains unestablished and absolute risk appears small.