MHRA Alert – Semaglutide and Risk of Vision Loss (NAION)

Safety Alert: Semaglutide and Non-arteritic Anterior Ischemic Optic Neuropathy

The MHRA has issued a safety update regarding a very rare but serious risk associated with semaglutide-containing medicines. Clinicians and responders should be aware of this potential adverse effect, particularly when counselling patients or assessing vision-related complaints.

What is NAION?

Non-arteritic anterior ischemic optic neuropathy (NAION) is a condition characterised by sudden vision deterioration, typically affecting one eye. It results from reduced blood flow to the optic nerve and can occur with little warning.

Key Points

• NAION has been very rarely reported in patients taking semaglutide
• Patients may present with sudden vision loss or blurred vision in one eye
• The condition requires urgent ophthalmological assessment
• Risk factors for NAION include age, hypertension, and diabetes

Affected Medicines

This alert applies to all semaglutide-containing products:

• Wegovy (weight management)
• Ozempic (type 2 diabetes)
• Rybelsus (type 2 diabetes)

Recommended Actions

• Advise patients to seek immediate medical attention if they experience sudden vision loss or changes in vision
• Consider NAION in the differential diagnosis of acute vision loss in semaglutide users
• Review patient risk factors at each consultation
• Document any vision-related concerns in patient records

Further Information

For the full MHRA safety update, visit the MHRA Drug Safety Update page.