Canada’s Wegovy monograph flagged NAION in September 2026 and tells doctors to stop semaglutide
The US Food and Drug Administration ordered manufacturers of every glucagon-like peptide-1 receptor agonist approved in the United States to add a rare blinding eye condition to their product labelling on November 9.
Canadian labelling has carried that warning for months.
The Health Canada-approved Wegovy product monograph on the Drug Product Database lists non-arteritic anterior ischemic optic neuropathy under Warnings and Precautions, Ophthalmologic, dated September, records it at a very rare frequency during semaglutide treatment, states there is no identified time interval for when it may develop after treatment starts, and directs that semaglutide be discontinued if it occurs.
NAION causes acute, painless, decreased vision in one eye, including permanent vision loss. It stems from decreased blood flow to the optic disc, the front part of the optic nerve, though the FDA states the underlying cause is not completely understood.
What the US order covers
Manufacturers of all 12 GLP-1 RA products listed by the agency, from exenatide approved in 2005 to orforglipron approved in 2026, must add NAION to the Warnings and Precautions section of their labelling.
Cases have been reported for all currently marketed GLP-1 RA products, according to the FDA drug safety communication issued November 9.
A meta-analysis of 126 randomized controlled trials covering 134,253 patients and 288,879 person-years of exposure identified 15 probable NAION events: 10 in patients treated with a GLP-1 RA, five on placebo, and none among patients taking other glucose-lowering medications.
Incidence reached 6.4 events per 100,000 person-years on GLP-1 RAs against 3.8 for comparators.
Published literature puts background NAION incidence at 2.3 to 10.2 cases per 100,000 persons per year in adults older than 50.
A retrospective cohort study in the FDA’s Sentinel Real-World Evidence Data Enterprise Commercial Network tracked adults with type 2 diabetes starting a GLP-1 RA, an SGLT-2 inhibitor, or a DPP-4 inhibitor between 2019 and 2024.
The FDA found no statistically significant increase against SGLT-2 inhibitors, at a hazard ratio of 1.19 with a 95 percent confidence interval of 0.91 to 1.54, and an increased risk against DPP-4 inhibitors, at a hazard ratio of 1.43 with a confidence interval of 1.02 to 2.01. Animal data reviewed by the agency identified no mechanism for the risk.
A Novo Nordisk spokesperson told Reuters that “Novo continues to believe the data do not establish a cause-and-effect relationship and we remain confident in the benefit-risk profile of our GLP-1 medicines.”
An Eli Lilly spokesperson told Reuters the company is carefully evaluating the update and will respond to the FDA promptly.
The European Medicines Agency’s safety committee found in June 2025 that NAION was a very rare side effect of semaglutide, affecting up to 1 in 10,000 people taking it for at least one year, per Reuters.
Canadian plan claims
Prior authorization requests for Wegovy and Zepbound rose more than 50 percent between 2025 and 2026 across the plans TELUS Health supports for prior authorization, Vicky Lee, pharmacist and director of pharmacy consulting and professional services at TELUS Health, told Benefits and Pensions Monitor in reporting on three years of GLP-1 claims.
Eligible spend on Ozempic and its generics fell about 40 percent across the TELUS Health book even as claim volume rose, Lee said, with the net reduction across semaglutide overall at about 23 percent.
Health Canada authorized Zepbound on June 16 for moderate to severe obstructive sleep apnea in adults with obesity, per BPM’s coverage of the approval and its formulary questions.
