- Semaglutide, the active ingredient in Ozempic and Wegovy, is linked to a rare blinding disease, new research suggests.
- This disease, known as non-arteritic anterior ischemic optic neuropathy (NAION), causes sudden blindness due to a lack of blood flow to the optic nerve.
- Despite the results, the study does not demonstrate a cause-and-effect relationship between the drug and NAION.
Semaglutide, the blockbuster drug used in Ozempic and Wegovy, has been linked to a rare blinding disease.
Patients with type 2 diabetes and obesity who take semaglutide appear to be at higher risk of nonarteritic anterior ischemic optic neuropathy (NAION) than those prescribed a non-GLP-1 medication. NAION is a condition that causes sudden blindness, usually in one eye, due to a lack of blood flow to the optic nerve. There is no known treatment for this condition.
The results, presented in the journal
“I’m going to start mentioning this as a warning to a patient, but I’m not going to say that because you’re obese and you have diabetes and you’re taking this drug, you’re going to go blind,” Yin Allison Liu, MD, PhD, associate professor of neuro-ophthalmology at the University of California, Davis, told Healthline. She was not affiliated with the study.
NAION is an elusive disease whose exact cause is not known.
“Ischemic optic neuropathy is very common in older diabetic patients with vasculopathic risk factors, although its pathogenesis is not completely understood,” Nicholas J. Volpe, MD, a neuro-ophthalmologist and chairman of the department of ophthalmology at Northwestern University Feinberg School of Medicine, told Healthline. Volpe was not involved in the research.
Researchers at Massachusetts General Brigham used patient data to look for a retrospective correlation between semaglutide and NAION over a one-year period. They studied two cohorts, each representing one of the FDA-approved indications for semaglutide: obesity and type 2 diabetes. In total, records from nearly 17,000 patients were included in the study.
Of these patients, 710 had type 2 diabetes and 979 were overweight or obese.
Among patients with type 2 diabetes, the mean age was 59 years and more than half were women. The age of overweight or obese patients was younger, averaging 47 years, and 72% were women.
The study authors asked a simple question: Were patients in this group more or less likely to develop NAION if they were prescribed semaglutide or a non-GLP-1 drug?
They found a clear signal.
Patients with type 2 diabetes were more than four times more likely to be diagnosed with NAION; obese patients were more than eight times more likely to be diagnosed.
Over the one-year period, 17 cases (8.9%) of NOIAN were observed among patients taking semaglutide in the diabetic cohort, but only six (1.8%) among those taking a drug other than GLP-1. The results were even more pronounced among overweight and obese patients: 20 cases of NOIAN (6.7%) occurred in patients taking semaglutide, compared with only 3 (0.8%) in those not taking semaglutide. It is unclear whether these cases were related to semaglutide or whether they were confounded by the higher risks associated with obesity and type 2 diabetes.
Volpe reiterated to Healthline that while the results demonstrate an association, much more research is needed.
“This does not establish causation. This does not establish danger. This does nothing other than draw attention to this fact and the potential need for us to think about it and study it more carefully,” he said.
Patients and health care providers should discuss the risks and benefits of any medication in the context of each individual’s personal situation and medical history.
“If I were a patient who wanted to take this type of medication, I would have no hesitation, based on this study, in thinking that I would go blind,” Volpi said.
Non-arteritic anterior ischemic optic neuropathy (NAION) is a rare condition that causes sudden blindness in one eye, often after waking up. It is caused by a lack of blood flow (ischemia) to the optic nerve, which connects the eye to the brain. The condition is rare, occurring in only 2 to 10 people in 100,000. It is the second most common cause of blindness due to optic nerve damage, after glaucoma.
The cause or pathogenesis of NAION is not yet well understood, although it is generally thought to be associated with vasculopathic risk factors, including diabetes, hypertension, and hypercholesterolemia.
“Although we have known about this disease for 75 years, it was first described or recognized in the 1950s, but we as neuro-ophthalmologists have never firmly established that only people with high blood pressure or only people with diabetes have it,” Volpe said.
The most important risk factor for NAION is an anatomical condition known as “disc at risk” or cupless optic nerve: when the structure of the eye itself causes congestion of the optic nerve fibers.
“With this condition, blood flow or oxygen delivery to the eyes can be relatively compromised when other confounding factors are present,” Liu said.
More controversial evidence has suggested that other common drugs, including
Although it is a serious complication, NAION is a rare disease with little known causes. “We know as much about the pathogenesis of this disease today as we did 31 years ago when I did my fellowship in neuro-ophthalmology,” Volpi said.
In a retrospective observational study, researchers found that patients with type 2 diabetes or obesity who took semaglutide were more likely to develop a rare blinding disease than those taking a non-GLP-1 drug.
This disease, known as nonarteritic anterior ischemic optic neuropathy (NAION), causes sudden blindness in one eye, often upon waking in the morning.
Experts told Healthline that the results are still early and do not demonstrate a cause-and-effect relationship. Patients should consult their doctor about the risks and benefits of the medications they are prescribing.