Now that they’ve been on the market for several years, Ozempic — the injectable GLP-1 agonist drug for treating diabetes — and its lower-dose version, the weight loss “miracle” Wegovy — are practically household names. 

But the active ingredient in both, semaglutide, hasn’t been without concerns, the least of which may be acid reflux, nausea and vomiting, acute pancreatitis and gallbladder disease — tied to the way the drug works by slowing the passage of food through the digestive tract.

There’s also the black box warning for thyroid cancer.

We expect drugs to have drawbacks, even trade-offs. But proponents of semaglutide say the health benefits of weight loss, especially when comorbidities like diabetes and high blood pressure exist, outweigh the risks.

But for semaglutide the risks keep piling up…

Ozempic’s potential for vision loss

A paper published in JAMA Ophthalmology by scientists from Harvard Medical School has uncovered a huge potential trade-off…

Their findings suggested an association between semaglutide and non-arteritic anterior ischemic optic neuropathy (NAION), an irreversible and uncommon condition causing damage to the optic nerve and, ultimately, permanent loss of vision.

“We were motivated to do this study purely because of our experience,” Joseph F. Rizzo III, MD, principal investigator, said. “I had seen a patient who had NAION, and she was on Ozempic. I was meeting with my trainees the same day, and I was telling them about this when a resident walked in and said that she had just seen a case like that in the emergency room. Later that week, I saw a third case. Three cases within 7 or 8 days were very odd, I thought. That’s when I began to develop the strategy to do a clinical study.”

The study consisted of 16,827 patients referred to and evaluated at Mass Eye and Ear, one of the country’s largest neuro-ophthalmology clinics, from December 1, 2017, through November 30, 2023.  

• Of 710 patients with type 2 diabetes, 194 had been prescribed semaglutide while 516 had been taking non–GLP–1 RA antidiabetic medications.
• Of 979 overweight/obese patients, 361 had been taking semaglutide, while 618 had been taking non–GLP–1 RA weight-loss medications.
• Among the two groups, the hazard ratios for NAION were 4.28 and 7.64 respectively.

Dr. Rizzo concluded that patients should be informed of this potential risk, but because their study was observational, more research was needed before broad changes could be made.

Now, two Danish studies have confirmed his team’s findings, and in a much larger study population…

Danish studies confirm NAION association

The first Danish study was conducted by Dr. Jakob Grauslund, Professor of Ophthalmology at the University of Southern Denmark (USD).

Dr. Grauslund and colleagues examined data from all 424,152 Danes with type 2 diabetes. They found that Ozempic more than doubles the risk of developing NAION.

They’ve also seen an increase in cases of NAION in Denmark since Ozempic came on the market there in 2018, rising from 60-70 a year to up to 150.

In the second study, Dr. Anton Pottegard and colleagues from USD looked at the number of patients in Denmark and Norway who developed NAION after starting treatment with Ozempic compared with people who used another medication to treat diabetes.

They found that Ozempic carried a 2.81 times greater relative risk of developing NAION. This means that a patient with type 2 diabetes who takes Ozempic, has almost three times the risk of developing NAION as those who don’t use the drug.

The Danish researchers emphasized the importance of treating diabetes, and that NAION is a serious, but rare side effect. They hope their results can be used by doctors and patients to discuss the pros and cons of treatment with Ozempic.

Things to consider

It’s always best to talk to a doctor before changing the way you take any medication that has been prescribed. And that’s part of the advice offered by The American Academy of Ophthalmology and the North American Neuro-Ophthalmology Society following the results of the Harvard study.

They do not recommend that people stop taking semaglutide unless they experience sudden vision loss — in which case they say to stop taking the drug and see a doctor immediately.

NAION symptoms include:

• Blurred vision
• Color distortion
• Loss of peripheral vision
• A dark or gray spot in the vision that doesn’t move
• Loss of contrast or light sensitivity

They also acknowledged that the medical community has been aware of other vision changes with semaglutide for some time, including that semaglutide can cause blurred vision, worsening of diabetic retinopathy and macular complications. However, they go on to say these appear to be temporary side effects.

They also suggest anyone taking semaglutide should talk to their doctor to be sure the medication is right for them.

We will stay on top of this news and if they issue a new statement based on the results of the Danish studies, we will share it.

Sources:

Danish diabetes medicine increases the risk of severely debilitating eye condition — EurekAlert

Risk of nonarteritic anterior ischemic optic neuropathy in patients prescribed semaglutide — JAMA Ophthalmology

Specialists discuss concerns over impact of semaglutide on the eye — Healio News

Use of semaglutide and risk of non-arteritic anterior ischemic optic neuropathy: a Danish-Norwegian cohort study — medRxiv

American Academy of Ophthalmology and North American Neuro-Ophthalmology Society Issue Advice on Weight Loss Drug and Eye Health — American Academy of Ophthalmology Newsroom