There has been some amused talk of prescribing sildenafil (famously known as Viagra, much less famously as Revatio) for pulmonary hypertension. How strange it is that doctors are now prescribing an erectile dysfunction drug for potentially life threatening conditions. The logic behind the alternative uses is sound enough: they all deal with regulating blood flow to other parts of the body. But I think the funny part is that all the “alternative” uses are way closer to what the developers were originally trying to do.
A drug of many uses.
For all the talk in scientific circles about a field needing to be “sexy” in order to to get funding, that erectile dysfunction doesn’t actually really fit that bill. The makers actually set out to treat angina and high blood pressure, because heart disease is a top killer and as long as something is a top killer in the Western world, there tends to be funding.
Before drug makers can look into how effective a drug is at treating a disease, they have to prove that it is safe to give to humans at all. So the first stage of clinical trials is to test the drug on a group of healthy volunteers to determine safe dosage. But healthy is a relative sort of term, and those volunteers often have some sort of ailment that can lead to accidental discoveries. This is how Gravol/Dramamine was found to relieve motion sickness.
And when they did the initial trials for sildenafil, well, they had some very happy “healthy” volunteers. There were already a large number of heart disease related drugs. But drugs for erectile dysfunction? That niche was completely unfilled at the time. And so Pfizer went through the remaining phases of clinical trials for a different condition than they originally intended.
And much to their delight it worked and Viagra hit the market accompanied by a ludicrous amount of advertising. It was a real gift to satirical television. And of course, our spam folders have never recovered from all the emails touting a cheap source.
Then other drugs entered the erectile dysfunction marketplace, eroding their market share (hard to not have that happen when it was previously the only game in town…). Prescriptions started leveling off despite the relentless ads. Apparently people aren’t quite as interested in the product as spam would have you believe.
Not exactly your typical drug development pathway
Drug companies love off label uses for existing products. They’ve already proved it’s safe for human consumption (though in this case there is an even bigger issue than usual with the safety data only being from male subjects), so they get to save a bunch of time skipping straight to proving it actually works on the disease they say it will. It just isn’t usually a case of the drug company deciding “Hey, wait a second, what if we tried it on that thing we were going to be using it for in the first place!”. The patent for sildenafil as Revatio for pulmonary hypertension actually predates the one where they called it Viagra and used it to treat impotence. But, well, we all got a little distracted sometimes and take a while to get back to what we originally meant to do.