FDA Issues Blindness Risk Warning for GLP-1 Weight Loss Drugs

The US Food and Drug Administration (FDA) has issued a new warning for GLP-1 class drugs—including Novo Nordisk's Ozempic and Wegovy, and Eli Lilly's Mounjaro and Zepbound—due to a rare eye condition that can lead to permanent blindness.

The US Food and Drug Administration (FDA) has requested that information regarding the risk of non-arteritic anterior ischemic optic neuropathy (NAION) be added to the warning labels of all GLP-1 class medications used in weight loss and diabetes treatment. NAION is defined as a rare condition that occurs with a sudden reduction in blood flow to the optic nerve, causing painless, sudden vision loss and permanent loss of vision in one eye. Having common risk factors such as diabetes, smoking, hypertension, and high cholesterol, the condition is the most common cause of acute optic nerve damage in individuals over 50, occurring at an annual average rate of 2.3 to 10.2 cases per 100,000 people in this age group, and currently has no reversible treatment.

The FDA began examining the potential link between GLP-1 drugs and NAION following a study published in the journal JAMA Ophthalmology in 2024, which identified an increased risk of NAION in patients using GLP-1s. Reviewing 126 clinical trials involving more than 134,200 patients, the agency identified 15 potential NAION cases, noting that 10 occurred in GLP-1 patients and 5 in individuals receiving a placebo. The FDA found an incidence rate of 6.4 cases per 100,000 patient-years among GLP-1 patients, while this rate was recorded as 3.8 cases for those taking a placebo or alternative glucose-lowering drugs.

A spokesperson for Novo Nordisk stated to The Guardian that they believe existing data does not establish a cause-and-effect relationship and that they continue to have confidence in the benefit-risk profile of GLP-1 medications. Meanwhile, an organization called the Access to Medicine Foundation has warned that the focus of pharmaceutical companies on GLP-1 weight loss drugs could jeopardize the global insulin supply.