Weight Loss Drugs Ozempic and Wegovy Linked to Vision Loss

Semaglutide, the active ingredient in popular weight loss drugs sold under brand names like Ozempic and Wegovy, has been linked to a condition that causes vision loss, according to a new study published on July 3, 2024 in JAMA Ophthalmology. In the study, patients who were prescribed semaglutide were more likely to develop non-arteritic anterior ischemic optic neuropathy (NAION)—a condition that involves lack of sufficient blood flow to the optic nerve and can cause vision loss and blindness—compared to those taking other medications for type 2 diabetes and weight management.¹

The study found that eleven percent of patients treated with semaglutide for diabetes over the past six years developed NAION, compared to just three percent of those treated with alternative diabetes medications. Additionally, seven percent of patients using semaglutide for weight loss developed NAION, in contrast to only one percent of matched peers using other weight loss medications. The research, which was conducted by scientists at Harvard University, was prompted by anecdotal reports from doctors in Boston who observed three of their patients taking semaglutide experiencing vision loss within just one week of starting the drug.²

NAION is a relatively rare condition that disrupts blood flow to the optic nerve and can lead to eye strokes, vision loss and blindness. People who have hypertension, obstructive sleep apnea, and diabetes are at highest risk doe NAION following semaglutide drug use. The findings mirror previous research that showed semaglutide worsens diabetic retinopathy, which involves damage to the blood vessels of the retina, in those with the chronic eye condition. The study did not include tirzepatide, a similar class of GLP-1 drugs sold under the brand name Mounajro.^{1 3}

Use of Weight Loss Drugs Has “Exploded”

In a recent press release, Joseph Rizzo, MD, lead author of the study, called the results “significant but tentative.” “This is information we did not have before, and it should be included in discussions between patients and their doctors, especially if patients have other known optic nerve problems like glaucoma or if there is pre-existing significant visual loss from other causes,” Dr. Rizzo said.¹

“The use of these drugs has exploded throughout industrialized countries and they have provided very significant benefits in many ways, but future discussions between a patient and their physician should include NAION as a potential risk,” Rizzo shared, highlighting the importance of providing patients with informed consent regarding the popular weight loss drugs. “He  added that, “It is important to appreciate, however, that the increased risk relates to a disorder that is relatively uncommon.”²

“Not Uncommon” for Rare Side Effects to Surface Years After FDA Approval

Pharmacoepidemiologist Mahyar Etminan, PharmD, a drug safety expert at the University of British Columbia in Vancouver, Canada noted that rare new side effects can surface years after approval by the U.S. Food and Drug Administration (FDA). “It’s not uncommon,” he says. Since pre-approval clinical trials typically only include a few thousand people, it’s not until the drug has been widely used by hundreds of thousands or even millions of people that other previously undetected risks or side effects surface.⁴

Vioxx, one of the deadliest drug recalls in FDA history, initially received expedited FDA approval and remained on the market for five years before being withdrawn. It is estimated that the pain killing drug caused over 60,000 deaths.

In some cases, new safety warnings can arise decades after approval. Cipro, an antibiotic approved in 1987, saw a significant update in 2008 when the FDA added a warning to fluoroquinolone antibiotics like Cipro. This boxed warning highlighted an increased risk of tendon ruptures. Since then, the FDA has continued to add more safety warnings and changes to the labels of these medications.^{4 5 6}

Novo Nordisk, one of the top pharmaceutical companies globally with significant revenue growth in 2023 and Europe’s largest drug company boasting a market capitalization exceeding $500 billion, maintains that th its semaglutide drugs are safe. “Patient safety is a top priority for Novo Nordisk, and we take all reports about adverse events from the use of our medicines very seriously,” a spokesperson for the Ozempic drugmaker said in a statement about the study indentifying a potential NAION risk.⁷

The latest findings add to an already extensive list of documented risks with semaglutide drugs, including gastroparesis (or stomach paralysis), suicidal thoughts, and an increased risk of all types of thyroid cancers. The American Academy of Ophthalmology noted that people in the study did develop NAION after their first dose of semaglutide but maintains the drug has been rigorously studied and is safe for use.^{1 8}

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