Regulator Warns of Rare Eye Disorder Risk with GLP-1 Diabetes and Obesity Drugs

The medicines regulator has issued a new safety warning for GLP-1-based drugs, like Ozempic, which could potentially cause a rare but serious eye disorder.

The Therapeutic Goods Administration's (TGA) warning covers the following glucagon-like peptide-1 (GLP-1) receptor agonists, which are used to treat type 2 diabetes and obesity:

Semaglutide, sold as Ozempic, Wegovy

Tirzepatide, sold as Mounjaro

Dulaglutide, sold as Trulicity

Liraglutide, sold as Saxenda

The TGA said the products had the potential to cause an eye disorder called non-arteritic anterior ischaemic optic neuropathy (NAION).

"(NAION) may result in permanent visual impairment, including blindness, and no treatment has been shown to improve visual acuity outcomes," the TGA's safety warning said.

NAION is caused by a disruption in blood flow to the optic nerve at the back of the eye and typically presents suddenly upon waking and without pain.

The regulator said anyone taking GLP-1 medicines should be alert to any signs of vision loss, stop taking the medicine and seek urgent medical attention if any changes were noted.

So far, 36 cases of the eye disorder associated with GLP-1 drugs have been reported on the national database of adverse events, the TGA said.

Twenty-three of those were among people taking semaglutide, three were taking liraglutide and 10 were using tirzepatide.

The TGA said it first identified the potential association between GLP-1 drugs and NAION in 2024 when a study was published in the Journal of the American Medical Association (JAMA) Ophthalmology.

The study examined almost 17,000 US patients and found those prescribed semaglutide had a higher risk of NAION than those taking non-GLP-1 medications for diabetes.

The TGA said since this study it conducted its own independent assessment of the potential association between GLP-1 RAs and NAION and sought advice from the Advisory Committee on Medicines.

Optometry Australia, which represents the largest community of optometrists in Australia, has said patients should not be unnecessarily alarmed by this update and do not need to stop taking a GLP-1 drug unless they have a change in their vision.

The professional body advised optometrists to ask patients presenting with sudden or unexplained vision loss whether they were currently using, or had recently used, a GLP-1 medicine.

Optometrist and vision scientist Dr Flora Hui from the Centre for Eye Research Australia said around 70 per cent of people did not recover their vision and someone's risk of developing NAION also increased if they had diabetes, sleep apnoea or hypertension.

People are also anatomically disposed to NAION if they have a crowded optic disc. The optic disc is where the optic nerve connects to the retina and when it is crowded, nerve fibres are more vulnerable to blood supply problems.

Dr Hui said people should not panic about the TGA's updated advice.

"There is a small risk of developing NAION with these drugs so making informed choices are important, especially if you have many of the risk factors associated with NAION," she said.

"Reduce your other risk factors associated with NAION by improving heart health, blood pressure and cholesterol.

"Most importantly, have regular eye tests with your optometrist or ophthalmologist whilst you're being treated and letting them know that you're taking these medications."

Professor Garron Dodd, head of the Metabolic Neuroscience Laboratory at the University of Melbourne, thinks there is still a question mark over whether the GLP-1 based drugs actually cause NAION considering most people taking the drug already have known risk factors.

"Nearly all the evidence is retrospective, drawn from insurance claims and electronic health records … separating the drug from the condition it treats is the hard part, and no study has managed it cleanly."

He said it was important people did not stop taking their medication on the basis of this safety update.

"For someone with type 2 diabetes or significant obesity, the cardiovascular, kidney and metabolic benefits [of these medications] are large and well-established, and stopping abruptly carries its own risks, so any change should be a conversation with your prescriber," he said.

Last June, the World Health Organization issued a warning about the risk of NAION from semaglutide medicines and The European Medicines Agency (EMA) recommended updating product information.

The EMA said NAION was a very rare side effect that potentially affected up to one in 10,000 users.