Blindness Risk from Ozempic and Wegovy Mirrors that of Viagra

A new study finds a concerning increase in risk of blindness with popular semaglutides

• The reported risk of blindness adds to the list of disclosed side effects from semaglutides including: depression, kidney failure, pancreatitis, thyroid cancer, gallbladder issues, severe stomach problems.

  

A new study finds a concerning increase in risk of blindness with weekly use of popular semaglutides: Ozempic for diabetes and Wegovy for obesity.

The type of blindness is called nonarteritic anterior ischemic optic neuropathy or NAION. Experts describe it as a sort of stroke in the retina of the eye. It is painless, non-treatable, and typically irreversible.

NAION is the same form of blindness associated with erectile dysfunction (ED) drugs such as Viagra. I broke that story globally in 2005 on CBS News.

With Viagra, I was surprised that it was an eye doctor rather than the original prescribing doctors, such as urologists, who did the detective work that revealed this pattern of blindness.

With Ozempic, it is also eye specialists who are noting the vision-related side effect.

Read on for details.

Podcast version of this Substack is below.

While many were initially brushing off the reports regarding Viagra nearly 20 years ago, I combed through the database of adverse event reports, found additional studies, and saw an obvious pattern—not only with blindness but also with hearing loss in Viagra patients. Both blindness and hearing loss were eventually added to Viagra’s warning label and those of other ED drugs.

If the government had more rigorous reporting requirements and more efficient monitoring of reported medicine side effects to the federal database, then the FDA would be alerting us promptly to risks of prescription drugs— sooner than we often hear about through other means. As it stands, any delays in getting the word out benefits the pharmaceutical industry. The longer it takes to put a warning on a drug or pull it off the market for safety reasons, the more of the drug that can be sold in the meantime to unsuspecting patients.

Pfizer initially tried to discredit the notion of a link between Viagra and blindness, saying none had shown up in its studies.

Regarding semaglutides, according to the new study in the International Journal of Retina and Vitreous:

During five years of observation of all persons with T2D in Denmark, use of once-weekly semaglutide independently more than doubled the risk of NAION. Given the irreversible nature of NAION, it is important to acknowledge this risk, and upcoming studies should aim to identify high-risk subgroups.

NAION is a tricky disorder, as I learned while covering the Viagra issue. Sometimes the vision loss is preceded by patients seeing changes in color. Maybe they see a lot of blues, for example, after taking Viagra. Some people begin losing their ability to see color. The vision loss is painless, so some patients continued taking Viagra even after they noticed a difference in color perception; or blurriness, a shadow, or a blind spot in their vision. The actual loss of vision, when it occurs, is typically sudden and is noticed after the patient wakes up. It usually affects one eye. Doctors say it cannot be reversed.

There are other risks with semaglutides, as there are with all medicines. Some are not known for years after many patients have taken a medicine under real world conditions. One of the most serious disclosed risks is thyroid cancer. As described on the drug’s label:

Semaglutide injection may increase the risk that you will develop tumors of the thyroid gland, including medullary thyroid carcinoma (MTC; a type of thyroid cancer). Laboratory animals who were given semaglutide developed tumors, but it is not known if this medication increases the risk of tumors in humans. Tell your doctor if you or anyone in your family has or has ever had MTC or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2; condition that causes tumors in more than one gland in the body). If so, your doctor will probably tell you not to use semaglutide injection.

According to Wegovy’s FDA approved label, the medicine may also cause:

Depression or thoughts of suicide.

Inflammation of your pancreas (pancreatitis). This could be signalled by severe pain in your stomach area (abdomen) that will not go away, with or without vomiting. You may feel the pain from your abdomen to your back.

Gallbladder problems, including gallstones.This could be signalled by pain in your upper stomach (abdomen), fever, yellowing of the skin or eyes (jaundice), or clay-colored stools.

Increased risk of low blood sugar (hypoglycemia), which can be serious, especially for those who also take medicines for diabetes such as insulin or sulfonylureas. Signs and symptoms may include dizziness or light-headedness, blurred vision, anxiety, irritability or mood changes, sweating, slurred speech, hunger, confusion or drowsiness, shakiness, weakness, headache, fast heartbeat, or feeling jittery.

Kidney problems (kidney failure). This may cause diarrhea, nausea, and vomiting, which may cause dehydration, which may worsen kidney problems.

Severe stomach problems.

Change in vision in people with type 2 diabetes.

Increased heart rate while at rest.

Food or liquid getting into the lungs during surgery or other procedures that use anesthesia or deep sleepiness (deep sedation).

The most common side effects may include: nausea, diarrhea, vomiting, constipation, stomach (abdomen) pain, headache, tiredness (fatigue), upset stomach, dizziness, feeling bloated, belching, low blood sugar in people with type 2 diabetes, gas, stomach flu, heartburn, and runny nose or sore throat.

The FDA considers semaglutides safe and effective when used as directed, or they would not be permitted to be sold.

A transcript of my original CBS News report on Viagra follows:

Feds Eye Viagra-Blindness Reports by Sharyl Attkisson, CBS News

May 26, 2005

Federal health investigators are looking into reports that some men who used Viagra may have suffered a new and very serious side effect -- blindness.

Twenty-three million men worldwide have used Viagra. A very small number of them are going blind after taking normal doses. [It’s important to note that even a handful of serious side effect reports can be worrisome, since experts say most illnesses from medicine are never recorded, and one injury can imply anywhere from 10,000 to 100,000 more.]

CBS News has learned from the FDA that it is urgently meeting about it with experts and Pfizer.

Jimmy Grant started using Viagra in 1998, when he was 57. At first, he felt pressure in his temples and saw color changes in his vision.

"I noticed the symptoms probably within 45 minutes to an hour," he told CBS News correspondent Sharyl Attkisson.

Soon, he went blind in his right eye. Doctors didn't make a connection to Viagra.

"After your loss of vision, did you continue taking doses?" Attkisson asked.

"On occasions, I did," he said. "And then in March 2000 after taking Viagra I experienced loss of sight -- partial loss of sight in my left eye.”

With both eyes damaged, a friend found an article on the Internet about Viagra and blindness, and Grant put two-and- two together.

"What convinced me that Viagra did it was what Dr. Pomeranz had in his report.”

That's Dr. Howard Pomeranz, an eye specialist who appears to be the first doctor to make a connection in one of his patients back in '98. To him, it made sense that Viagra -- which alters blood flow in key parts of the body -- could also affect circulation to the optic nerve.

"And so I thought, well, in both of these situations, blood flow is being altered, so maybe there is a connection between the two," said the University of Minnesota neuro-ophthalmologist.

He published his patient's case looking for feedback. By 2001, he had five cases to report to the FDA and Pfizer, the makers of Viagra. Slowly, more reports trickled in.

"So they certainly are aware of this possible side effect of their medication," Pomeranz said.

The FDA tells CBS News it's looking at about 50 reported cases of vision loss and, while no direct link has been proven, an FDA medical supervisor says "We're very concerned. This issue is front and center, it's a priority. We know people need to know as promptly as possible.”

Pfizer told us its Viagra studies show no report of vision loss and say there is no more evidence of vision loss in men taking Viagra than those who don't. However Pfizer confirmed it in in discussions with the FDA to update the labels to reflect the rare occurrences.

Jimmy Grant is now spending retirement in a way he never imagined: living with his 83-year-old mother, suing Pfizer, and sorry he ever tried Viagra.

"I've pretty much accepted that my eyesight is not going to come back. But I've also pretty much accepted that Viagra done it," he said.

The FDA says it's monitoring adverse event reports for the similar drugs in the same class as well.

Update December 29, 2024: Below you can read the original statement Pfizer issued, basically saying Viagra doesn’t cause blindness. But the company later was required to add the risk to the warning label.

2005 Pfizer Statement Regarding Viagra:

A review of 103 Viagra clinical trials involving 13,000 patients found no reports of non-arteritic anterior ischemic optic neuropathy (NAION). Outside of clinical trials, Viagra has been used by more than 23 million men worldwide over the past seven years and reports of visual field loss due to NAION are extremely rare.

There is no evidence showing that NAION occurred more frequently in men taking Viagra than men of similar age and health who did not take Viagra.

NAION is the most common acute optic nerve disease in adults over age 50 and it shares a number of common risk factors with erectile dysfunction: age over 50, high blood pressure, high cholesterol, diabetes. Most of the reported cases in which NAION has occurred in men taking Viagra have involved patients with underlying anatomic or vascular risk factors associated with the development of NAION. This makes it impossible to determine whether these events are caused by the patient’s underlying vascular risk factors, anatomical defects, Viagra or a combination of these factors -- or to other factors.

Pfizer is in discussions with the Food and Drug Administration to update the Viagra label to reflect these rare ocular occurrences. Viagra has a strong safety profile and remains an effective medication that benefits millions of patients.

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Read Sharyl Attkisson’s five star bestseller: Follow the Science: How Big Pharma Misleads, Obscures, and Prevails.