UK Health Regulator Issues Alert on Ozempic and Wegovy Blindness Risk
The Medicines and Healthcare products Regulatory Agency (MHRA) has issued a stark warning regarding weight loss injections such as Ozempic and Wegovy, highlighting a potential link to a rare condition that can cause sudden blindness. This alert follows reports of non-arteritic anterior ischemic optic neuropathy (NAION) in individuals using these semaglutide-based medications.
Understanding the Rare Side Effect
NAION is a serious medical condition that results in a sudden loss of vision in one eye due to reduced blood flow to the optic nerve. The MHRA has emphasised that while this side effect is associated with semaglutide, the risk is extremely small, potentially affecting only up to one in 10,000 users. Despite this low probability, the agency is urging heightened vigilance among patients and healthcare professionals.
Semaglutide is marketed under two primary brand names: Wegovy, which is prescribed for weight management, and Ozempic, used in the treatment of Type 2 diabetes. Both drugs function by mimicking the hormone glucagon-like peptide 1 (GLP-1), which slows digestion and suppresses appetite, often leading to significant weight loss of up to 20% of body weight.
Immediate Action Required for Vision Changes
The MHRA's guidance is clear and urgent. Patients taking semaglutide who experience any sudden changes in their eyesight, such as blurred or clouded vision, or a rapid deterioration in one or both eyes, should seek emergency medical attention immediately. The agency advises attending an eye casualty unit if available locally, or otherwise going straight to A&E.
Dr Alison Cave, the MHRA's Chief Safety Officer, stated: "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 crucial that patients and healthcare professionals remain alert to the associated symptoms."
Context and Broader Implications
This warning comes at a time when an estimated two million people in the UK are using some form of weight-loss injection, with semaglutide products leading the market. NAION is recognised as the most common cause of sudden nerve blindness that can result in permanent damage, though experts are still uncertain why weight loss jabs might trigger this condition.
Common side effects of these medications include nausea and stomach cramps, and they typically require ongoing specialist support to maintain weight loss. Many patients discontinue treatment due to factors such as cost, intolerable side effects like vomiting, or plateauing weight loss. Without accompanying lifestyle changes, stopping the injections often leads to regaining lost weight, and muscle mass lost during treatment is usually not recovered.
The manufacturer of semaglutide, Novo Nordisk, has previously emphasised that these drugs are part of a well-established class of medicines, rigorously studied in clinical trials, with patient safety being paramount. The MHRA continues to provide updated guidance on the potential side effects and safe usage of semaglutide, encouraging any adverse reactions to be reported via the Yellow Card scheme to aid ongoing monitoring and research.
