The UK’s health watchdog has updated safety information for semaglutide, a medication commonly prescribed for type 2 diabetes and weight management, warning that the drug may cause a very rare side effect called non-arteritic anterior ischemic optic neuropathy (NAION).
Semaglutide, a GLP-1 receptor agonist, is marketed under brand names including Rybelsus and Ozempic for diabetes, and Wegovy for weight loss. The treatment works by reducing appetite and increasing insulin secretion, offering significant benefits for patients managing blood sugar levels and body weight.
While semaglutide is generally considered safe, a 2024 study reported rare cases of vision loss linked to the drug. Experts explained that the medication could potentially trigger an “eye-stroke,” occurring when the arteries supplying blood to the eyes become blocked.
In the UK, only three cases of NAION have been reported since semaglutide was first authorized in 2018, making the condition extremely rare. Nevertheless, health authorities have updated guidance to alert patients and healthcare professionals about the potential risk.
NAION results from reduced blood flow to the front portion of the optic nerve and can cause sudden, painless vision loss, typically affecting one eye.
Dr Alison Cave, Chief Safety Officer at the Medicines and Healthcare products Regulatory Agency (MHRA), said: “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 important that patients and healthcare professionals are alert to the associated symptoms.”
The MHRA advises patients taking semaglutide to seek urgent medical attention if they experience a sudden change in their eyesight, including rapid vision deterioration in one or both eyes. As a result, semaglutide prescriptions will now carry a warning regarding this potential risk.
Novo Nordisk, the manufacturer of Ozempic and Wegovy, confirmed that patient safety remains a top priority. A spokesperson told UNILAD:”We take any reports of adverse events from the use of our medicines very seriously and work closely with regulatory authorities worldwide to monitor safety. Product information and patient leaflets for Wegovy, Ozempic, and Rybelsus have been updated to include NAION under special warnings and precautions, and as an adverse drug reaction, listed as ‘very rare’ (affecting up to 1 in 10,000 patients).”
The company added that current evidence does not suggest a causal relationship between semaglutide and NAION, and they continue to regard the benefit-risk profile of semaglutide as favorable.
