Popular jab linked to risk of vision loss in new study prompting warning

Semaglutide, which was first designed for diabetes patients, gained popularity over the last year as a potential game-changer in the fight against obesity. But now a study has linked the medication to the risk of sudden vision loss, prompting a warning.

Better known by its brand names like Ozempic and Wegovy, could come with a serious side effect, scientists said. The drug works by mimicking a hormone that helps regulate blood sugar and appetite. It was approved for NHS use by the National Institute for Health and Care Excellence (NICE) last year.

Wegovy is the brand name for semaglutide, which is licensed and approved for managing overweight and obesity. It is manufactured by Novo Nordisk and is recommended by the National Institute for Health and Care Excellence (NICE) for managing overweight and obesity in some patients on the NHS.

In a study by researchers at Massachusetts Eye and Ear and Harvard Medical School, published in JAMA Ophthalmology, it was revealed that patients taking semaglutide could be at a raised risk of developing a condition called nonarteritic anterior ischemic optic neuropathy (NAION).

NAION occurs when blood flow to the optic nerve is suddenly reduced or blocked and can lead to rapid and often permanent vision loss, usually in one eye. It is a rare condition affecting only two to 10 people per 100,000 in the general population.

The study showed that among patients with type 2 diabetes, those taking semaglutide were more than four times more likely to develop NAION compared to those on other diabetes medications. This risk was even greater for overweight or obese patients using semaglutide for weight loss, as they were more than seven times more likely to experience NAION than those using other weight loss drugs.

Study co-author Dr Joseph Rizzo explained: “The use of these drugs has exploded throughout industrialised 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. It is important to appreciate, however, that the increased risk relates to a disorder that is relatively uncommon.”

However, the study didn’t prove that semaglutide directly causes NAION. Dr Rizzo added: “Our findings should be viewed as being significant but tentative, as future studies are needed to examine these questions in a much larger and more diverse population.

“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.”

In response to the findings, a spokesperson for Novo Nordisk, which produces semaglutide, said: “Patient safety is a top priority for Novo Nordisk, and we take all reports about adverse events from use of our medicines very seriously.

“Nonarteritic anterior ischemic optic neuropathy (NAION) is not listed as a known adverse drug reaction in the summary of product characteristics (SmPC) for the marketed formulations of semaglutide (Ozempic and Rybelsus for type 2 diabetes and Wegovy for weight management) as per the approved labels.”

They also pointed out that the study is not designed to assess any potential causal relationship between NAION and semaglutide exposure, and other factors such as smoking, duration of diabetes and optic disc morphology were not considered in the analysis.