MHRA updates product information regarding the very rare risk of non-arteritic anterior ischemic optic neuropathy (NAION) in patients taking semaglutide.
The Medicines and Healthcare products Regulatory Agency (MHRA) has today (5 February 2026) updated product information for healthcare professionals and patients regarding the risk of the very rare occurrence of non-arteritic anterior ischemic optic neuropathy (NAION) in patients taking semaglutide.
Semaglutide is a glucagon-like peptide-1 receptor agonist (GLP-1RA) sold under the brand names Ozempic and Rybelsus, prescribed for patients with type 2 diabetes; and also as Wegovy, which is indicated for weight management and cardiovascular risk reduction in patients who are overweight or obese.
NAION is an extremely rare ischemic event which occurs due to reduced blood flow to the front portion of the optic nerve which typically causes sudden, painless vision loss in one eye. Patients who have experienced NAION describe it as a blurring or cloudiness of vision.
Patients taking semaglutide who notice a change in their eyesight, such as sudden impairment to their vision, or if their eyesight gets worse very quickly in one or both eyes, should urgently attend eye casualty (if available in the area) 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 https://yellowcard.mhra.gov.uk/ scheme."
Guidance on potential side effects of semaglutide and on its safe and effective use
