Wegovy and Ozempic: Understanding the Risk of Vision Loss
Recent research has highlighted a potential link between the diabetes drug Ozempic and the weight loss medication Wegovy, both containing semaglutide, and an increased risk of sudden vision loss. While these medications offer significant health benefits, including reduced blood sugar levels, slowed digestion, and appetite suppression, understanding the potential risks is crucial for both patients and healthcare providers.
What is Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION)?
The study, published in the British Journal of Ophthalmology, identified a connection between Wegovy and a condition called non-arteritic anterior ischemic optic neuropathy (NAION). Often referred to as an “eye stroke,” NAION causes sudden and usually permanent vision loss due to reduced blood flow to the optic nerve 1. Although relatively rare, affecting approximately one in 10,000 people taking semaglutide, researchers found a “potential dose-dependent safety concern” associated with the drug 2.
Wegovy vs. Ozempic: What the Study Found
The research analyzed reports of side effects submitted to the U.S. Food and Drug Administration (FDA) between December 2017 and December 2024. Canadian researchers compared reports associated with different dosages and formulations of semaglutide:
- Ozempic: Up to 2mg weekly injection for type 2 diabetes.
- Wegovy: Up to 2.4mg weekly injection for obesity (the highest approved dose).
- Rybelsus: Daily tablet for type 2 diabetes.
- Mounjaro (tirzepatide): Also examined for comparison.
The study revealed that Wegovy had the strongest association with sudden vision loss. Patients taking Wegovy for weight loss had a fivefold greater chance of developing NAION compared to those taking Ozempic for diabetes 1. Men were found to be at a three times greater risk than women. Notably, the study found no increased risk associated with Rybelsus tablets or tirzepatide (Mounjaro).
Why the Difference? Dosage and Administration
Researchers believe the higher doses of Wegovy and its injectable form, which leads to faster action, may explain the increased risk. In contrast, Rybelsus, administered as a daily tablet, has limited absorption and a slower uptake, potentially explaining the lack of a detectable link to NAION 3.
Regulatory Response and Safety Updates
Both the UK Medicines and Healthcare products Regulatory Agency (MHRA) and the European medicines regulator have issued warnings regarding the potential risk of NAION associated with semaglutide 1. Dr. Alison Cave, the MHRA chief safety officer, emphasized that the risk remains extremely low but stressed the importance of awareness among patients and prescribers regarding the symptoms of potential side effects 1.
Novo Nordisk, the manufacturer of Wegovy, Ozempic, and Rybelsus, has updated patient leaflets to include information about NAION. However, the company maintains that the available evidence does not establish a causal relationship between semaglutide and NAION, and that the benefit-risk profile of the drug remains favorable 1.
What Does This Mean for Patients?
Samantha Mann, a consultant ophthalmologist, cautions that the study relies on reported side effects and cannot definitively prove causation or determine the true prevalence of the issue. She highlights the need for further research to clarify the increased risk.
If you are taking Wegovy, Ozempic, or Rybelsus, it is essential to be aware of the symptoms of NAION, which include sudden, painless vision loss. Prompt medical attention is crucial if you experience any changes in your vision.
Key Takeaways
- Wegovy is associated with a higher risk of NAION (sudden vision loss) compared to Ozempic.
- Higher doses and injectable formulations may contribute to the increased risk.
- Regulatory agencies have issued warnings, and patient leaflets have been updated.
- Patients should be aware of the symptoms of NAION and seek immediate medical attention if they experience vision changes.