MHRA issues a UK drug safety update on semaglutide and NAION
UK regulators said semaglutide may very rarely cause a sudden vision-loss condition called NAION, and that Ozempic, Wegovy and Rybelsus labeling there will be updated [1].
Britain's Medicines and Healthcare products Regulatory Agency (MHRA) published a Drug Safety Update on February 5, 2026, telling prescribers and patients that semaglutide — sold as Ozempic and Rybelsus for type 2 diabetes and as Wegovy for weight management and cardiovascular risk reduction — has been very rarely linked to non-arteritic anterior ischemic optic neuropathy (NAION), a condition that can cause sudden vision loss, usually in one eye [1][3].
The agency said the Summary of Product Characteristics and Patient Information Leaflet for semaglutide products in the UK "will be updated in the coming months" to describe the risk and to advise that anyone reporting sudden vision loss be urgently referred for an eye exam [1]. The MHRA's press release on the same day was headlined as an update to product information, so the two documents describe the timing slightly differently [3].
What the numbers show
NAION happens when blood flow to the front of the optic nerve drops. It usually causes sudden, painless loss of vision in one eye, often described as blurring or cloudiness [1][3]. People with type 2 diabetes are already at higher risk, and smoking, high blood pressure and high cholesterol also raise risk [1].
The MHRA classified the risk as "very rare," meaning it may affect up to 1 in 10,000 people taking semaglutide [1][3]. A European review of clinical trial data, post-authorization reports and published literature suggested that semaglutide exposure in adults with type 2 diabetes may be tied to roughly a two-fold increase in the relative risk of NAION — about one extra case per 10,000 people treated per year [1].
Background rates vary widely depending on the study. Among people with type 2 diabetes, published estimates range from 11.4 to 82 cases per 100,000 person-years [1]. In the general population aged 40 and older, estimates run from 7.73 to 11.5 per 100,000 person-years, rising to 14.79 per 100,000 person-years in people 60 and older [1].
UK spontaneous reporting has been sparse. Since semaglutide was first authorized in the UK in 2018 through August 1, 2025, the MHRA's Yellow Card scheme received three reports suggestive of NAION with semaglutide, against an estimated 10.2 million packs dispensed over the past five years [1][3]. The agency stressed that a report does not prove the medicine caused the event, only that the reporter suspected a link [1].
The MHRA's expert advisers, the Pharmacovigilance Expert Advisory Group of the Commission on Human Medicines, noted "conflicting evidence in the literature" but agreed with updating the product information [1]. The European review covered only semaglutide; the MHRA said it is reviewing whether there is evidence of an association with other GLP-1 agonists [1][3].
Why it matters for patients
This is a UK regulatory action, not a US one, and it does not change the FDA-approved labeling for Ozempic, Wegovy or Rybelsus in the United States. A July 2026 roundup published by a plaintiffs' drug injury law firm reported that the US Ozempic prescribing information revised in May 2026 still did not carry a NAION warning, and that lawsuits over vision loss were being filed against Novo Nordisk [2]. That source is not a regulator, and the current status of any US labeling change is not established by the MHRA documents.
The practical content of the UK advice centers on symptom awareness. The MHRA told clinicians that patients reporting sudden loss of vision, including partial loss, should be urgently referred to an ophthalmologist, and that semaglutide should be discontinued if NAION is confirmed [1]. It also flagged that privately prescribed semaglutide may not show up in a patient's medical record, so clinicians should ask about it when someone arrives with these symptoms [1].
MHRA Chief Safety Officer Dr. Alison Cave said the "potential risk of NAION for patients prescribed semaglutide is extremely small," but that patients and clinicians should be alert to the symptoms [3].
What happens next
The MHRA said UK product information will be revised "in the coming months" from the February 5, 2026 update; no specific date was given [1]. The agency's review of other GLP-1 receptor agonists is ongoing, and no findings or timeline for it have been published [1][3].
Sources
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