The US Food and Drug Administration (FDA) announced additional warnings about rare side effects on labels of all GLP-1 drugs used for blood sugar regulation and weight loss, including popular medications Ozempic, Wegovy, Zepbound, and Mounjaro. This follows data linking these drugs to non-arteritic anterior ischemic optic neuropathy (NAION), which can cause permanent vision loss. The FDA advises users experiencing unusual visual symptoms to seek medical attention immediately.
The US FDA has required new warnings about the risk of vision loss on labels of GLP-1 drugs, which are used to treat obesity, diabetes, and other conditions, including Ozempic, the Wegovy weight loss pen, Zepbound, and Mounjaro.
The side effect involves non-arteritic anterior ischemic optic neuropathy (NAION), caused by reduced blood flow to the optic nerve, potentially leading to severe or permanent vision loss, although the exact mechanism is not yet fully understood.
This warning follows medical research published in 2024 that found a connection between NAION and users of semaglutide, the active ingredient in Ozempic and Wegovy.
The FDA’s analysis of over 125 clinical trials found that about 6 out of every 100,000 GLP-1 users developed NAION after at least one year of use, compared with fewer than 4 per 100,000 among those using placebos or other blood sugar-lowering drugs.
Symptoms to watch for include blurred vision, partial vision loss, color distortion, or other visual abnormalities. The FDA recommends that anyone experiencing these symptoms contact healthcare professionals immediately.
A neuro-ophthalmology expert involved in the research said that evidence suggests GLP-1 drugs may increase NAION risk, but patients are not advised to stop taking the drugs, as they offer significant benefits to many.
NAION can also occur in people not using GLP-1 drugs, with an incidence of about 2 to 10 cases per 100,000 people over age 50, according to the American Academy of Ophthalmology.
Novo Nordisk, manufacturer of Ozempic and Wegovy, stated that current data do not confirm a causal relationship between their drugs and NAION, emphasizing patient safety as a top priority. Eli Lilly, maker of Zepbound and Mounjaro, said it is carefully evaluating updates to warnings about sudden optic nerve ischemia.
Experts warn that vision loss from NAION is usually irreversible and may worsen even if the patient stops the medication. Severity in one eye does not predict damage in the other eye.