Semaglutide and non-arteritic anterior ischemic optic neuropathy (NAION)

Non-arteritic anterior ischemic optic neuropathy (NAION) is a condition affecting the optic nerve head (ONH)

• typically causes sudden, painless vision loss, usually in one eye that is often described as a blurring or cloudiness of vision
• due to reduced blood flow to the front portion of the optic nerve.
  • termed ‘non-arteritic’ because this reduction in circulation occurs without inflammation of the blood vessels, distinguishing it from arteritic causes
  • hypertension, diabetes, and nocturnal hypotension are risk factors (1)

The European Medicines Agency (EMA) has reviewed all available data on NAION with semaglutide, including data from non-clinical studies, clinical trials, post-marketing surveillance and the medical literature, and has concluded that NAION is a very rare side effect of semaglutide (meaning it may affect up to 1 in 10,000 people taking semaglutide) (2).

Advice for Healthcare Professionals (3):

• semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist used to treat type 2 diabetes mellitus and for weight management and cardiovascular risk reduction
• semaglutide treatment may be very rarely associated with NAION, a condition which can cause vision loss, typically in one eye
• NAION typically causes sudden, painless vision loss in one eye that is often described as a blurring or cloudiness of vision.
• privately prescribed semaglutide may not appear on the patient’s medical history so if a patient presents with these symptoms, enquire about semaglutide use
• patients reporting a sudden loss of vision (including partial loss) should be urgently referred for specialist examination by an ophthalmologist
• discontinue semaglutide treatment if NAION is confirmed
• advise new patients, or existing patients during medication reviews, to urgently attend eye casualty or A&E if they experience a sudden loss of vision or rapidly worsening eyesight
• report suspected adverse drug reactions associated with semaglutide, including NAION, on a Yellow Card

Reference:

1. Desai N, Patel MR, Prisant LM, Thomas DA. Nonarteritic anterior ischemic optic neuropathy. J Clin Hypertens (Greenwich). 2005 Feb;7(2):130-3.
2. EMA (June 2025). Pharmacovigilance Risk Assessment Committee (PRAC) concludes eye condition NAION is a very rare side effect of semaglutide medicines Ozempic, Rybelsus and Wegovy.
3. MHRA Drug Safety Update volume 19, issue 7: February 2026: 1