Australians taking popular weight-loss and diabetes medicines are being urged to watch for sudden vision loss after a new safety warning linked the drugs to a rare eye disorder.

The Therapeutic Goods Administration (TGA) says the condition, known as non-arteritic anterior ischaemic optic neuropathy (NAION), can cause permanent vision impairment and, in some cases, blindness.

The warning applies to medicines widely prescribed to treat type 2 diabetes and obesity, including Ozempic, Wegovy, Mounjaro, Trulicity and Saxenda.

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The prescription drugs have become household names thanks in part to their dramatic weight-loss effects and a number of celebrities, including Oprah Winfrey, Whoopi Goldberg and Amy Schumer, publicly discussing their use.

People taking any of the medicines now have been urged to be alert for any signs of vision loss, with the TGA saying “no treatment has been shown to improve visual acuity outcomes” once NAION develops.

“If you or someone you care for is using one of the GLP-1 RA medicines listed above, you should be alert to any sign of vision loss,” the regulator said.

“If any changes are noted, stop using the medicine and seek prompt medical attention.”

The warning relates to a rare eye condition that may result in permanent vision impairment, including blindness. Credit: AAP/7NEWS

Health professionals have been advised to urge patients to seek urgent medical attention if they experience sudden or partial vision loss.

According to the regulator’s Database of Adverse Event Notifications, 36 cases of optic ischaemic neuropathy have been reported in Australia among people taking GLP-1 medicines.

Of those, 23 involved semaglutide (Ozempic and Wegovy), 10 tirzepatide (Mounjaro) and three liraglutide (Saxenda).

No cases were linked to dulaglutide (Trulicity), although one person who developed the condition while taking semaglutide had previously used dulaglutide.

Updated safety information for Ozempic and Wegovy says some studies suggest an increased risk of NAION, although there is “no identified time interval” for when it may develop after treatment begins.

The product information also notes people born with a particular optic nerve structure, known as a “disc at risk”, are already at higher risk of developing the condition.

The TGA said this underlying risk can be assessed by an optometrist or ophthalmologist.

The latest warning adds to a growing list of safety considerations surrounding the blockbuster medicines, following recent concerns they can also contribute to muscle and bone loss without regular weight-bearing exercise.

The Consumer Medicine Information leaflets for the medicines will also be updated to reflect the latest safety advice.