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

The FDA said Monday that every GLP-1 maker must slap a new warning on its labels about a rare eye condition that can cause sudden, permanent blindness. The condition, nonarteritic anterior ischemic optic neuropathy — NAION — hits the optic nerve that carries signals from eye to brain. Cut off blood flow to that nerve and vision can vanish without pain. There is no known treatment, and the damage sticks.

The requirement covers the whole class: Novo Nordisk's Ozempic and Wegovy, Eli Lilly's Mounjaro and Zepbound, plus several older GLP-1 diabetes drugs. Both companies said patient safety comes first. The FDA's own wording is blunt about the risk: there is a potential increased risk of rare NAION for people on these drugs.

The alarm traces back to a 2024 study in JAMA Ophthalmology that found diabetes patients prescribed semaglutide were four times as likely to develop NAION as those who weren't. The FDA reviewed side-effect reports in its adverse event monitoring system and crunched data from multiple clinical trials. NAION cases have now been reported for every GLP-1 currently on the market — though agency scientists still couldn't pin down how the drugs might raise the risk.

Part of the difficulty: NAION's risk factors overlap heavily with the conditions GLP-1 patients already have, including Type 2 diabetes, sleep apnea and hypertension. It's the second most common optic nerve disease in the U.S., striking up to 10 out of 100,000 people over 50, per the American Academy of Ophthalmology. The FDA's message to patients and caregivers: watch for a potential increased risk of NAION, which can cause acute, painless vision loss in one eye, including permanent vision loss.

These labels were already crowded. Novo and Lilly's GLP-1 drugs carry warnings for pancreatitis, gallbladder problems and kidney injury, plus a black box — the FDA's strongest alert — over a possible thyroid tumor risk.