FDA requires warning labels for GLP-1 drugs over rare blindness risk

The U.S. Food and Drug Administration announced on Monday that manufacturers of glucagon-like peptide-1 (GLP-1) drugs must include a warning about a potential increased risk of nonarteritic anterior ischemic optic neuropathy (NAION), a rare eye disease that can lead to sudden, permanent blindness. NAION occurs when blood flow to the optic nerve is reduced, causing acute, painless loss of vision in one eye.

The agency’s directive applies to all GLP-1 products on the market, including Novo Nordisk’s Ozempic and Wegovy, as well as Eli Lilly’s Mounjaro and Zepbound, along with older GLP-1 diabetes treatments. The FDA said the requirement follows a 2024 JAMA Ophthalmology study that found patients with type 2 diabetes taking semaglutide were four times more likely to develop NAION than those not using the drug. Review of adverse-event reports and clinical-trial data showed cases of NAION associated with every currently marketed GLP-1 medication, though scientists have not identified a biological mechanism linking the drugs to the condition.

"Patients and caregivers should be aware of a potential increased risk of NAION, a rare condition that can result in acute, painless, decreased vision in one eye, including permanent vision loss," the FDA statement read.

Risk factors for NAION overlap with common conditions in GLP-1 users, such as type 2 diabetes, sleep apnea and hypertension. The American Academy of Ophthalmology estimates NAION affects up to 10 per 100,000 people over age 50, making it the second most common optic-nerve disease in the United States.

Spokespersons for Novo Nordisk and Eli Lilly said patient safety remains a top priority. Both companies already list other safety warnings on their labels, including risks of pancreatitis, gallbladder problems, kidney injury and, under a black-box warning, potential thyroid tumors.