The US Food and Drug Administration (FDA) has announced that it will require manufacturers of popular weight loss and diabetes medications, including Ozempic, Wegovy, Zepbound, and Mounjaro, to add a new warning to drug labels regarding a potential increased risk of a rare eye condition that can lead to permanent vision loss.
The Nature of the Condition and Challenges of Association
The condition being warned about is Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION), a condition that occurs due to restricted blood flow to the optic nerve, causing swelling, cell death, and permanent nerve damage that leads to sudden vision loss, which is often irreversible. This condition is considered extremely rare in the general population, occurring at a rate of two to 10 people per 100,000, according to the American Academy of Ophthalmology.
The assessment of the relationship is complicated by the fact that the risk factors for the aforementioned optic neuropathy are the same as those commonly found in patients taking GLP-1 drugs, such as diabetes, cardiovascular disease, high blood pressure, high cholesterol, metabolic syndrome, and sleep apnea.
Conflicting Data and Previous Studies
The first signals regarding this link appeared in 2024 through a study conducted by researchers at Harvard University and published in the journal JAMA Ophthalmology, which found higher rates of optic neuropathy among semaglutide users compared to others. However, the study faced limitations, including its reliance on a single referral center and high baseline incidence rates there.
This was followed by additional studies and analyses with conflicting results; while some research did not observe any general association, others indicated slight increases in specific cases compared to certain diabetes medications. For its part, the US FDA conducted a meta-analysis involving 126 trials and more than 130,000 patients, identifying a few potential cases that prompted its decision to impose the new warnings, thereby partially aligning with a previous review by the European Medicines Agency (EMA).
What Changes Practically?
Unlike the European agency, which recommended completely stopping the medication if the condition is confirmed, the US FDA and the American Academy of Ophthalmology have taken a more flexible stance. They have advised healthcare providers to consider discontinuing GLP-1 treatment for patients who show symptoms of the condition only if the benefits of the treatment do not clearly outweigh the risks, while emphasizing the importance of shared decision-making between the patient and the treatment team.