Chapter 140
Viagra: A Tough Nut to Crack
Hippocrates wrote about the Scythians, a horse-riding people, that “the vast majority of them become impotent.” What does it look like with stationary bikes and other modern steeds? In the United States alone, 50 million people ride bikes, and there are concerns about repeated pressure on the pelvic nerves that branch off from the spine, pass in an arc between the legs, and run up to the genitals. At first glance, cyclists have the same ED rates, but since cyclists tend to be younger, you have to account for age. A systematic review with meta-analysis compared 3000 cyclists with age-matched non-cyclists and concluded that cyclists are at a significantly higher risk.
But aren’t there bicycle saddles with a hole in the middle that are supposed to reduce pressure on the perineum? They could make everything even worse! The key pelvic nerve, the pudendal nerve (Nervus pudendus), and the associated artery do not run down the middle, but through the Alcock canals on both sides, and the reduced seating surface of cutout saddles could actually increase pressure rather than reduce it. Cyclists who use such hole saddles have up to a sixfold higher ED risk, but the danger appears to be limited to those who simultaneously experience numbness in the perineum. What can you do about it? Most of the pressure on the critical region comes from leaning forward. When you sit upright, the penis is supplied with 40 percent more oxygen than when you lean forward at a 60-degree angle. On longer rides, you can also regularly pedal while standing.
Viagra: A Tough Nut to Crack
Cholesterol-lowering statins have been proven to help with ED, yet Viagra and similar medications from the class of phosphodiesterase-5 inhibitors are considered first-line therapies. They relax the muscle fibers in the penis that normally constrict blood flow. Until the “lecture that changed sexual medicine,” it was thought that erections arose not from dilation of the supplying blood vessels, but rather from blood no longer draining out of the penis. The lecture that Professor Giles Brindley gave in 1983 at the annual meeting of the American Urological Association included a demonstration. Before taking the podium, the speaker injected a muscle relaxant into his penis. To underscore his point, he not only pulled it out in the middle of the lecture, but waddled and wiggled with his pants down to the front row to let it be examined more closely. The organizers were “not happy … because there were quite a few wives in the audience.”
Viagra is taken orally and works similarly. It began as a failed chest-pain drug with a happy, multibillion-dollar side effect. Nevertheless, in the United States, between 32 and 69 percent of users discontinue it after one to two years. About half of men therefore conclude that the disadvantages outweigh the advantages, which include lack of effectiveness, the cost, and side effects, the worst of which is non-arteritic anterior ischemic optic neuropathy (NAION). As I explain in more detail in see.nf/naion, with NAION (a pupil infarction), you typically wake up in the morning and can’t see out of one eye anymore, rarely both, with vision loss that may be temporary, but doesn’t have to be.
Men who don’t like medications still have the option of surgery—and a penile prosthesis. It sounds unbelievable, but penile implants have been used since the 16th century. In early experiments, patients had their own rib cartilage or entire ribs implanted into the penis. The rib gave men a “permanent erection,” but with the “Flexirod” technique from the 1960s, they got to keep their ribs, and the implant had a joint in the middle so they could fold the device down and “better conceal” it. Of course, it depends on getting the right size: If implants are too small, the tip droops, leading to the “Concorde phenomenon” (the drooping tip resembles the bent nose of the Concorde). But implants that are too long can also be a problem if the semi-rigid construction rubs in the glans. Ouch!
Today there are inflatable prostheses, and one day it may be possible to develop ones made of “expanding foams that respond to external magnetic fields,” or made of metal meshes “that can expand and contract like a cage.” (How would you get through airport security with that?)
It gets under the skin
Of the half dozen Viagra-type medications on the market, sildenafil (the actual Viagra) probably has the best effectiveness, but likely also the most side effects. Looked at closely, it is remarkably safe. For example, one man tried unsuccessfully to kill himself with 65 tablets. But now that we’ve had Viagra for more than 20 years, the first chronic side effects could be emerging. These include glaucomas, one of the leading causes of blindness. In glaucoma, the optic nerve degenerates, and among long-term Viagra users, the risk of developing it is increased by up to tenfold. But the main reason the medical community is reconsidering the safety of this medication class is cancer risk.
I go through the evidence in my video see.nf/viagra, but in short, melanomas are also made invasive by a gene mutation that throttles the enzyme phosphodiesterase-5, which medications like Viagra do, and that may help explain why people who take Viagra, Cialis, Levitra, and the like have a significantly higher risk of developing this deadly form of skin cancer.
False hope
For Internet Viagra, one analysis found that only 18 percent of the pills were genuine. Some were contaminated, for example with other medications, including amphetamines, or with ordinary commercial paint. On the other hand, “natural” products to enhance sexual function are among the dietary supplements most commonly contaminated with pharmaceuticals. More than a dozen deaths have been attributed to taking sexual-enhancement products because the pills were laced with diabetes medications that sent dozens of people into a coma from low blood sugar. Wait a second. Don’t some supplement manufacturers claim their products are verified and clean based on independent testing? Well, there is what’s called dry labbing, a dirty little secret of supplement manufacturers, in which testing labs simply stamp fake certificates. You can find a list of other misdeeds by supplement makers in see.nf/supplements.
A particularly outrageous example is the story of BMPEA (beta-methylphenethylamine), documented on the news website STAT, one of my favorite sources for medical journalism. A Harvard researcher published an article about the FDA finding an amphetamine-like designer stimulant in various dietary supplements sold in the United States. In response, one of the exposed companies, Hi-Tech Pharmaceuticals, maker of supplements named Black Widow and Yellow Scorpion, sued the researcher for defamation, libel, and disparagement of its products and initially demanded 200 million US dollars in damages.
Hi-Tech’s CEO openly admitted he had “hoped to silence this guy with it.” Although Hi-Tech ultimately failed in court, the lawsuit was a warning to other researchers. Hi-Tech’s CEO is said to have stated that he “hopes the long and costly legal battle will deter other scientists from taking a close look at the supplement industry.”
Supplements and ED
Are there any dietary supplements that work at all? I discuss the available data in see.nf/edpills. Vitamins A, B3, C, and E failed, and in studies on vitamins B6 and D in connection with ED, the control groups were missing in order to rule out a placebo effect or even to document that they do more than nothing.