Health officials warn weight-loss injections could cause sudden blindness as new safety labels added

The UK's health watchdog has announced it has updated its product information for semaglutide treatments, warning the drugs could cause a very rare side effect called NAION.

Semaglutide is a GLP-1RA treatment which works to reduce appetite and increase insulin secretion. It's commonly sold under brand names Rybelsus and Ozempic for type two diabetes and Wegovy for weight loss.

While there are many benefits to taking the drugs, one complication was reported in a 2024 study involving cases of vision loss.

Experts stated semaglutide could cause an 'eye-stroke' after the arteries supplying blood to the eyes become blocked.

This is extremely rare, with just three cases reported in the UK since semaglutide’s initial authorisation back in 2018.

Nonetheless, officials across the pond have updated their guidance, stating a condition known as non–arteritic anterior ischemic optic neuropathy (NAION) has been reported by some users of Wegovy.

Health officials have issued a new warning regarding weight-loss injections (Getty Stock Photo)

NAION is caused by decreased blood flow to the front area of the optic nerve, meaning sufferers can experience sudden, painless vision loss, typically in 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."

Patients taking semaglutide should visit the emergency room if they experience 'a sudden change in their eyesight'.

This includes a 'sudden impairment to their vision, or if eyesight gets worse very quickly in one or both eyes', according to MHRA.

Semaglutide prescriptions will now come with a warning regarding the risk of blindness.

Wegovy prescriptions now have a new warning (Peter Dazeley/Getty Images)

Novo Nordisk, the manufacturer of Ozempic and Wegovy, told UNILAD: "Patient safety is our top priority, and we take any reports about adverse events from the use of our medicines very seriously. We work closely with authorities and regulatory bodies from around the world to continuously monitor the safety profile of our products.

"The EU SmPC and patient leaflets for Wegovy, Ozempic (semaglutide injection) and Rybelsus (semaglutide tablets) have been updated to include 'Non-arteritic anterior ischemic optic neuropathy (NAION)' and under section 4.4 'Special warnings and precautions for use' and as an adverse drug reaction in section 4.8 'Undesirable effects' (frequency: very rare, meaning it may effect up to 1 in 10,000 people taking semaglutide).

"Based on the totality of evidence we concluded that the data did not suggest a reasonable possibility of a causal relationship between semaglutide and NAION and Novo Nordisk believes that the benefit-risk profile of semaglutide remains favourable."