The US Food and Drug Administration on Monday told patients and healthcare providers about a potential increased risk of a serious eye condition linked to GLP-1 drugs used for weight loss and diabetes. The condition is non-arteritic anterior ischemic optic neuropathy, known as NAION.
The agency said it is requiring GLP-1 drugs, including Eli Lilly’s Mounjaro and Zepbound and Novo Nordisk’s Ozempic and Wegovy, to add information about this risk to the “warnings and precautions” section of their labels.
What the FDA is asking drugmakers to change
The regulator said it reviewed clinical trial data, animal data and post-marketing data, including observational studies and case reports. Its safety communication applies to all medicines with GLP-1 receptor agonist activity.
NAION is a common cause of sudden, painless vision loss and may permanently impair sight in some cases. It is caused by reduced blood flow to the front part of the optic nerve, but its underlying cause is not fully understood.
Drugmakers respond to the eye risk warning
A Lilly spokesperson said the FDA communication does not refer to any findings specific to the company’s medicines. The company said it is carefully evaluating the update and will respond to the FDA promptly.
A Novo Nordisk spokesperson said the company continues to believe the data do not establish a cause-and-effect relationship. The company said it remains confident in the benefit-risk profile of its GLP-1 medicines.
Citi analyst Geoff Meacham said the action may temporarily increase patient and investor concern. He said, however, that the rarity of NAION and the substantial weight, blood sugar, heart, kidney and sleep apnea benefits should limit changes to prescribing.
Earlier findings on semaglutide and vision loss
Last year, the European Medicines Agency’s safety committee said NAION may affect up to 1 in 10,000 people taking semaglutide for at least one year. Semaglutide is the active ingredient in Wegovy, Ozempic and Novo’s diabetes drug Rybelsus. It was the first time a regulator had confirmed the side effect.
The Danish Patient Compensation Association had said last year that four patients in Denmark who lost vision after using Novo’s GLP-1 drugs were granted compensation. A large study published in 2025 tracked nearly 175,000 diabetic patients taking semaglutide and an equal number taking non-GLP-1 medicines. It found the risk of NAION more than doubled after two years of GLP-1 treatment compared with other diabetes medicines.
