FDA Requires Warning on All GLP-1 Drugs Over Potential Risk of NAION, a Rare Condition That Can Cause Vision Loss

The Food and Drug Administration on Monday, Nov. 9, required makers of all GLP-1 medications to add a warning about a potential increased risk of a rare eye condition. The condition, non-arteritic anterior ischemic optic neuropathy, or NAION, can cause permanent vision loss in one eye, the agency said.

Related: Novo Nordisk Earnings: Wegovy Pill Beats Forecasts as Novo Raises Outlook.

What the FDA ordered

The agency said application holders must add the information to the Warnings and Precautions section of labeling for all GLP-1 receptor agonist medications. Those drugs include Novo Nordisk’s Ozempic and Wegovy and Eli Lilly’s Mounjaro and Zepbound, STAT reported.

NAION is caused by decreased blood flow to the front part of the optic nerve, the FDA said. The underlying cause is not completely understood. STAT reported that the condition is sometimes called an “eye stroke” and has no proven treatments.

What the evidence showed

An FDA analysis of 126 randomized trials covering 134,253 patients found 6.4 NAION cases per 100,000 person-years among GLP-1 users. The rate was 3.8 among patients taking a placebo or another glucose-lowering drug. That is a difference of 2.6 cases per 100,000 person-years, by Boston Report calculation.

The analysis rested on small numbers. It identified 15 probable NAION events, 10 among GLP-1 users and 5 among patients on placebo, the FDA said.

A separate FDA study of adults with type 2 diabetes produced mixed results. It found no statistically significant increase in NAION risk compared with SGLT-2 inhibitors, with a hazard ratio of 1.19. It did find an increased risk compared with DPP-4 inhibitors, with a hazard ratio of 1.43.

The FDA said its review of animal data did not identify a mechanism for how the drugs could raise the risk. The agency said reports from its adverse-event system were hard to interpret because NAION risk factors overlap with conditions common among GLP-1 patients. NAION cases have been reported for all currently marketed GLP-1 products, it said.

A causal relationship has not been established, CNBC reported.

What patients should watch for

The FDA said symptoms include sudden, painless vision loss in one eye that patients may notice upon waking. Others are blurred or missing portions of vision, distorted colors and reduced central sharpness. Patients with these symptoms should contact a health care professional right away, the agency said.

Patients who have had a NAION event should discuss with their clinician whether to continue the drug, according to the FDA. The agency told clinicians to refer suspected cases promptly to an ophthalmologist and to consider stopping the drug unless the benefits clearly outweigh the risk. Risk factors may include smoking, diabetes, high blood pressure, sleep apnea, anemia and kidney disease, it said.

How the companies and analysts responded

Novo Nordisk said it “continues to believe the data do not establish a cause-and-effect relationship,” CNBC reported. The company said it remained confident in the benefit-risk profile of its GLP-1 medicines. CNBC said it had asked Eli Lilly for comment.

Citi analysts said the labeling action was “likely to attract attention but should have limited impact on GLP-1 uptake,” according to CNBC. More health coverage is on our health and science hub and our health news page.

Sources

• FDA: FDA Requires Safety Labeling Changes for GLP-1 Receptor Agonists Due to Potential Increased Risk of Rare But Serious Eye Condition
• CNBC: FDA warns of vision loss risk linked to popular GLP-1 drugs like Wegovy, Zepbound
• STAT: FDA warns GLP-1 drugs carry potential risk of rare eye condition

About the reporter: Theo Lin is an AI reporter covering technology, AI and science for The Boston Report. This article was produced with AI under our editorial policy. Read our AI and media disclosure.