The little blue pill that's put the bounce back into the step of millions of men is celebrating 15 years since it was approved for sale in the U.S., changing the conversation (sometimes for the worse) about sex and erectile dysfunction.

Pfizer's drug sildenafil, commonly known as Viagra, was authorized for sale by the U.S. Food and Drug Administration on this day in 1998, two years after it was first developed as a treatment for heart disease and high blood pressure.

Quick facts about Viagra: Originally developed as a cardiac drug to treat heart disease and high blood pressure

The latest 2010 statistics show 9.5 million perscriptions for Viagra were filled in Canada

Over 25 million men in the United States have tried Viagra

The World Anti-Doping Agency has studied the drug's effect on sport performance but hasn't listed it as a banned substance

In November 2012, the Supreme Court of Canada ruled overwhelmingly that Pfizer's patent that had created a 16-year monopoly to sell Viagra was void

The drug has gone on to become one of the most well known pharmaceutical brands, aided by its famed advertising campaign.

University of British Columbia professor Barbara Mintzes said Viagra's popularity also helped shift the language away from impotence towards sexual, or erectile dysfunction.

"The positive side of that is that there isn't this sort of implication that it's sort of a personal failure on a man's part if he has a sexual problem," she said.

But London, Ont.-based clinical psychologist Dr. Guy Grenier says that despite Viagra's success, it's actually "tremendously overprescribed" by health professionals who shy away from discussing sexual dysfunction with patients.

"For the people who are uncomfortable, they immediately reach for the prescription pad," Grenier told CBC Kitchener-Waterloo's The Morning Edition host Craig Norris. "When we've got that sort of quick immediate answer, we end up with people getting the wrong treatment."

Pfizer's website claims that to-date, over 25 million men in the United States have tried Viagra. Millions more know the commercials that depict middle-aged men experiencing a new zest for life.

Mintzes said alarming statistics used by companies such as Pfizer to describe the number of men suffering from erectile dysfunction are in most cases false.

"You'll see these rates of over half of men over 40 which is an enormous exaggeration of the true extent of the problem," she said. "If you look at some of the more qualitative research, interviews with men and women over how their sex lives have been affected, you see a much more nuanced view of what's gone on."

A chapter of Mintzes's co-authored book, Sex, Lies, and Pharmaceuticals, looks at Viagra, a pill she says has been "overmarketed" over the years as one that can fix any problem with your libido.

"It's a bit of teasing out where does the actual pill, and what it can or can't do, start and end compared to the myth and the story," she said.

Grenier notes that mixed results of the drug have led to a significant majority of men not renewing their prescription — in one study reaching as much as 70 per cent.

Doctors have also coined the term post-Viagra syndrome, used to describe men who have achieved an erection after taking the drug, but who still lack the desire or confidence to have sex.

"A lot of sexual performance issues have nothing to do with blood flow," Grenier said. "They have to do with relationships issues, or animosity, or attraction, or communication — all kinds of things."

Grenier said Viagra's strength continues to be its marketing power and recommends that people would benefit from more sex education.

"We have a very sexualized society but we remain a very sexual illiterate society," he said.