The Medicines and Healthcare products Regulatory Agency (MHRA) has updated guidance for healthcare professionals and patients on the extremely rare risk of non‑arteritic anterior ischemic optic neuropathy (NAION) in people taking semaglutide.

 

Semaglutide—a glucagon‑like peptide‑1 receptor agonist (GLP-1RA) sold as Ozempic and Rybelsus for type 2 diabetes, and Wegovy for weight management and cardiovascular risk reduction—has been linked to NAION, a sudden, painless loss of vision in one eye caused by reduced blood flow to the optic nerve. Patients often describe the condition as blurring or cloudiness of vision.

 

The MHRA urges anyone taking semaglutide who notices sudden visual changes, including rapidly worsening vision in one or both eyes, to seek urgent care at eye casualty (if available) or A&E.

 

Dr Alison Cave, MHRA’s Chief Safety Officer, said: "Patient safety is the MHRA’s top priority and we continually monitor the safety and efficacy of all licensed medicines. While the potential risk of NAION for patients prescribed semaglutide is extremely small, it is important that patients and healthcare professionals are alert to the associated symptoms. 

 

"If you, or someone you care for, is taking semaglutide and you notice sudden loss of vision in one eye, then we advise you to urgently attend eye casualty (if available in your area) or A&E and report it via our Yellow Card scheme.”

 

According to MHRA data, up to 1 August 2025, only three reports of suspected NAION linked to semaglutide were received through the Yellow Card scheme, out of roughly 10.2 million packs dispensed. Studies suggest the risk may affect up to about 1 in 10,000 users.