Active Ingredient in Ozempic Linked to Condition That Causes Blindness

A new study has linked the active ingredient in Novo Nordisk's Ozempic and Wegovy, to an eye condition that can cause blindness, a new study has found.

In the journal JAMA Ophthalmology, Harvard scientists found that patients who'd been prescribed semaglutide — a glucagon-like peptide-1 (GLP-1) agonist believed to mimic the stomach's feeling of fullness — were between four and seven times as likely to develop non-arteritic anterior ischemic optic neuropathy, a condition that blocks blood flow to eye nerves, than people prescribed other weight loss drugs.

Better known as NAION, the blockage effect of this condition that only affects 10 out of every 100,000 people can ultimately result in blindness, and as The Guardian notes, there's no known treatment for it, either.

To get to this jarring conclusion, the Harvard researchers analyzed data from more than 16,000 patients who received treatment at its Mass Eye and Ear Hospital over a six-year period. Of those patients, 710 had type 2 diabetes, 194 of whom had been prescribed semaglutide, and 975 were overweight, 361 of whom had been prescribed semaglutide.

For the subjects with type 2 diabetes — which is nominally required for an Ozempic prescription — there were 17 NAION events compared to only six who had been prescribed a different diabetes drug. Calculated into percentages, that means that 8.9 percent of people in the semaglutide cohort experienced NAION events, while just 1.8 percent of people on other drugs had them.

Among those who were overweight, the results were even more stark: of those 361 overweight patients had been prescribed semaglutide, 20 experienced NAION events over a three year period, while the other 614 who were prescribed a different weight loss medication suffered only three. In other words, those prescribed semaglutide were more than seven times as likely to have NAION event compared to those on other medications. Overall, 6.7 percent of those on semaglutide had NAION events compared to just 0.8 percent for overweight people on other weight loss drugs.

In a statement to The Guardian, Novo Nordisk, the Danish drugmaker behind Ozempic and Wegovy, said that although it takes "all reports about adverse events from use of our medicines very seriously," NAION is nevertheless not "listed as a known adverse drug reaction in the summary of product characteristics."

With so many other medical and mental health issues becoming associated with semaglutide, however, scrutiny is growing.

"Given the rapid increase in semaglutide use and its possible licensing for a range of problems other than obesity and type 2 diabetes, this issue deserves further study," Queen's University Belfast physiology professor Graham McGeown told The Guardian, "but possible drug side effects always need to be balanced against likely benefits."

More on semaglutide: Scary Counterfeit Ozempic Contains the Wrong Drug