US patients sue Ozempic, Mounjaro makers over vision loss

Dozens of patients have filed lawsuits in the United States against the makers of popular GLP-1 drugs, including Ozempic, Wegovy and Mounjaro, alleging that the medicines caused a rare form of sudden vision loss.

GLP-1 drugs are mainly used to treat type 2 diabetes, while some are also approved for chronic weight management.

The lawsuits concern non-arteritic anterior ischaemic optic neuropathy (NAION), a condition that occurs when blood flow to the optic nerve is reduced and can result in sudden, usually painless and permanent vision loss, ABC News reported on Tuesday.

The patients allege that the drugmakers did not adequately warn them about the potential risk.

The development comes as GLP-1 medicines become increasingly available in Nigeria, where a recent PREMIUM TIMES investigation found that the injections were being sold online without prescriptions or evidence of medical supervision.

What drugmakers say

Novo Nordisk, which makes Ozempic and Wegovy, rejected the claims, telling ABC News that it considers the lawsuits without merit and is defending them.

The company said it takes reports of adverse events seriously and continuously monitors the safety of its GLP-1 medicines.

Eli Lilly, which makes Mounjaro and Zepbound, said patient safety was its top priority and that it was monitoring and evaluating safety information about its medicines, including possible eye-related issues.

ABC News reported that the US Food and Drug Administration (FDA) is also reviewing a possible safety signal involving GLP-1 medicines and NAION.

What the evidence shows

Researchers have been studying a possible link between GLP-1 medicines and NAION since a 2024 report from a health centre in Boston suggested that people taking semaglutide, the active ingredient in Ozempic and Wegovy, could face an increased risk.

However, subsequent studies have produced mixed findings and no study has established that GLP-1 medicines cause NAION, according to ABC News.

The European Medicines Agency and Australia’s Therapeutic Goods Administration have identified NAION as a rare possible side effect of some of the medicines based on their reviews of available evidence.

The European Medicines Agency estimates that the condition could affect about one in 10,000 GLP-1 users with diabetes.

Al Jazeera reported that a US personal injury firm has filed more than 90 lawsuits against Novo Nordisk in a New Jersey state court since 2025 on behalf of patients who developed NAION while taking its products. Separate lawsuits have also been filed in Pennsylvania.

Nigeria’s online market

The development is relevant to Nigeria, where GLP-1 medicines have become increasingly available through social media and online vendors.

In its investigation, PREMIUM TIMES found that vendors were openly marketing Mounjaro and Ozempic online and selling the prescription medicines without requesting prescriptions or evidence of medical supervision.

Some vendors told PREMIUM TIMES that the injections had no side effects, despite warnings from manufacturers about possible adverse effects.

The investigation also found vendors marketing retatrutide, an experimental medicine that is still under clinical trials.

PREMIUM TIMES found that the injectables marketed by the vendors did not appear on NAFDAC’s public product registration database.

NAFDAC, in response to a Freedom of Information request, said medicines intended for commercial distribution in Nigeria are generally required to undergo registration before being marketed, although some unregistered medicines may be imported through “controlled access pathways” under defined conditions.

NAFDAC had previously issued alerts warning that Ozempic was not registered in Nigeria and that falsified versions of the medicine were circulating in the country.

The development in the US highlights the importance of medical supervision and reliable safety information.

People taking GLP-1 medicines who experience sudden, painless vision loss should seek urgent medical attention, according to ophthalmologists cited by ABC News.