The Australian Therapeutic Goods Administration (TGA) has warned that popular weight-loss and diabetes medicines, including Ozempic, Wegovy, Mounjaro, Trulicity and Saxenda, are linked to a rare eye disorder known as non-arteritic anterior ischaemic optic neuropathy (NAION). The condition, which occurs when blood flow to the optic nerve is disrupted, can cause sudden vision loss that may become permanent, the regulator said.

The TGA urged patients taking any of the medicines to be alert for signs of vision loss, including sudden loss of vision in one eye, blurred or dimmed vision, or missing areas in their field of vision. “If any changes are noted, stop using the medicine and seek prompt medical attention,” the regulator stated. Health professionals have been advised to tell patients to seek urgent medical attention if they experience sudden or partial vision loss.

Luke Arundel, chief clinical officer of Optometry Australia, stressed that the complication remains rare, potentially affecting up to one in 10,000 users. According to the TGA’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 notes that some studies suggest an increased risk of NAION, although there is “no identified time interval” for when it may develop after treatment begins. Established risk factors for NAION include diabetes, cardiovascular disease, high blood pressure, high cholesterol, obstructive sleep apnoea and smoking, Arundel added. The TGA also noted that people born with a particular optic nerve structure, known as a “disc at risk”, are more susceptible to the condition. The regulator said no treatment has been shown to improve visual acuity outcomes once NAION develops.