'Full Measure': Running the risk
WASHINGTON (Sinclair Broadcast Group) - Since Viagra was first approved to treat impotence in 1998, tens of millions of men have taken erectile dysfunction (ED) drugs, including Cialis and Levitra. In 2015 alone, Pfizer reported $1.2 billion in revenue from Viagra. As with all medicine, there are potential risks, including - rarely - permanent blindness. The eye doctor who first uncovered the possible link tells us how he discovered it by listening to a patient more than a decade ago, and now new evidence suggests it could affect more men than first thought.
Dr. Howard Pomeranz: "The patient used the drug shortly before wanting to initiate sex, actually didn't have sex, um, but noticed within, within an hour or less after taking the drug that he lost vision in one eye, um, and to me, that's something that's just beyond just circumstance."
Pomeranz is a neuroophthalmologist and associate professor at the Hofstra Northwell School of Medicine in New York.
Sharyl Attkisson: "It's very serious, but at the time at least the erectile dysfunction medicine had no such warning or hint of this."
Pomeranz began to hear about similar cases and in 2005 published reports of 14 patients who went blind shortly after taking Viagra. That’s when Attkisson began investigating and in May 2005 broke the news that the FDA was in serious talks with Pfizer to list blindness under possible risks.
Less than two months later, labels on Viagra, Cialis and Levitra added warnings about “permanent loss of vision” from “blood flow ... blocked to the optic nerve.”
Attkisson: "At the time the pharmaceutical industry put the warnings on the label, but insisted they really didn't think there was a link."
Pomeranz: "Correct, because this disease, ischemic optic neuropathy, has been associated with circulatory problems in the body - high blood pressure, diabetes, smoking and other conditions - and it's sometimes difficult to separate those confounding factors that a lot of patients who have ED have already."
Attkisson: "So, the FDA asked the three manufacturers at the time to conduct a study to try to answer this question?"
Pomeranz: "The FDA mandated that each of these three drug companies perform a prospective study."
In the decade since, only Pfizer has completed its FDA-mandated study. Published in 2015, it confirmed the possible blindness connection. But Pomeranz says few ophthalmologists read about it.
Attkisson: "So, the Pfizer study, when it was finally released, found what sort of risk?"
Pomeranz: "So, they calculated approximately a twofold risk of developing ischemic optic neuropathy within a 24-hour period after using Viagra or one of the other similar ED drugs."
Attkisson: "Over somebody that's not taking it."
Attkisson: "That's a significant risk in the medical world."
Pomeranz: "It is, um, I have patients who will ask me, you know, 'What is my risk of developing this problem if I take one of these drugs?' Now, at least I can tell patients there's some research that shows that there is some significant risk of you developing this problem after you, after you take the drug if you're someone who has risk factors for developing this problem."
Pfizer updated its warning label to reflect its new study. We asked Pfizer if it’s fair to say that its own study and label now indicate a link between Viagra and blindness. Pfizer pointed to the FDA-approved label which says it’s “not possible to determine whether [the cases of blindness are] related directly to the [drug] or other factors.” Pfizer also told us "this issue is rare and that there is no scientific certainty with regard to the cause." But Pomeranz found the risks could be greater than the 40 cases of blindness he says Pfizer identified.
Pomeranz: "I did some research into the FDA adverse events reporting database and found that there are literally hundreds of cases that have been reported to the FDA of ischemic optic neuropathy related to, um, ED drug use. I think it's vastly under-reported. There are probably lots of cases out there that we're not even aware of."
Since it's eye specialists, not the doctors who prescribe Viagra, who are most likely to see patients with vision loss, Pomeranz got the word out to fellow ophthalmologists at a recent conference.
Attkisson: "What was the response of your audience when you presented the numbers that were actually in the FDA system?"
Pomeranz: "They were aghast, because the peer review literature only shows 40 cases or so, the fact that there are hundreds of cases out there that have been reported to the FDA, I think just made people aware that, you know, we just don't know how many cases of this are, are out there."
Attkisson: "And to be clear, you're not saying that people shouldn't use ED drugs."
Pomeranz: "No, not at all, but I think people need to be aware that there is a potential risk to their vision if they, they use one of these drugs."
The makers of Levitra told us there's no conclusive evidence of a link. The makers of Cialis say blindness is very rare and its study is finished, but not yet released.