The U.S. Food and Drug Administration (FDA) on Monday required all glucagon-like peptide-1 receptor agonist medicines to carry a warning about nonarteritic anterior ischemic optic neuropathy (NAION), citing a possible link to lasting vision loss.
NAION affects the optic nerve and may abruptly reduce sight in one eye without pain; vision loss can be permanent, the FDA said. Its review covered 126 controlled trials, 134,253 participants and 288,879 person-years of exposure. Reviewers classified 15 cases as probable: 10 among patients receiving GLP-1 medicines, five in placebo groups and none among recipients of other glucose-lowering medicines outside the class. The estimated rate was 6.4 cases per 100,000 person-years for GLP-1 users, compared with 3.8 for a pooled group of placebo recipients and patients taking non-GLP-1 glucose-lowering drugs.
A separate FDA Sentinel analysis followed adults with type 2 diabetes who began treatment from 2019 through 2024. NAION rates were 30 to 32 cases per 100,000 person-years for GLP-1 drugs, 31 for sodium-glucose cotransporter-2 (SGLT-2) inhibitors and 26 for dipeptidyl peptidase-4 (DPP-4) inhibitors. The agency found no statistically significant increase compared with SGLT-2 treatment, but reported a higher risk compared with DPP-4 treatment.
Diabetes and other health conditions common among people prescribed GLP-1 medicines can also contribute to NAION risk, complicating efforts to determine whether reports stem from treatment or patients’ underlying health, the FDA said. Its review of animal data did not identify how the drugs might lead to the condition.
The label change covers medicines including Ozempic, Wegovy, Mounjaro and Zepbound. Mounjaro and Zepbound contain tirzepatide, which acts on GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptors.
The FDA advises patients to contact a health professional promptly for sudden vision loss, blurred or missing areas of vision, altered color perception or reduced sharpness at the center of their vision. Clinicians should promptly refer suspected cases to an ophthalmologist and consider stopping treatment if a patient develops NAION, unless the benefits clearly outweigh the risk.
In June 2025, the European Medicines Agency’s safety committee classified NAION as a “very rare” side effect of semaglutide medicines, a category covering up to one in 10,000 users. That review concerned semaglutide; the FDA’s new label requirement applies across the broader GLP-1 RA class.
