Starting Monday, Viagra will be facing stiffer competition. Viagra is the brand name for Pfizer's sildanefil, the erectile dysfunction (ED) drug that hit the market in 1998 and made it big, as in over 1.5 billion in revenues in 2016. But Viagra's patent is scheduled to expire in April 2020, which undoubtedly will give rise to a number of generic versions. But, as CBS News reported previously, a deal negotiated four years ago will allow Teva Pharmaceuticals USA Inc. to begin selling a generic version in the United States on December 11, 2017. Pfizer will counter with their own generic little white pill at half the current $65-a-little-blue-pill price.

This milestone could make sildanefil's impact even bigger. Viagra has already changed society in many ways. Prior to Viagra's arrival, hearing ED on television usually meant a talking horse or the emergency department. But things changed when the introduction of Viagra came in the year after the Food and Drug Administration (FDA) began allowing direct-to-consumer (DTC) advertising in 1997. Quickly ED went from something which was rarely mentioned (even between patients and doctors) to something that it is hard to miss when you watch any television, especially for more than 4 hours.

On the one hand, greater awareness and the availability of a medication option has helped the approximately 18 million men in the United States over the age of 20 who suffer from ED, based on a study published in the American Journal of Medicine led by Elizabeth Selvin, PhD, MPH from the Johns Hopkins Bloomberg School of Public Health. It also may have made it easier for people to discuss sexual health issues in general. Since sexual health is tied with mental, emotional, and physical health, Viagra could make a major difference for someone who has no other remaining options to address their ED. Here's an Associated Press segment on how generic versions of sildanefil will make it more affordable for patients:

However, the introduction of Viagra and its associated marketing has had its side effects. And by side effects, I don't mean aches or pains in the muscles, bloody nose, diarrhea, difficult or labored breathing, flushing, headache, trouble sleeping, sneezing, etc.

One issue is what's been dubbed "medical student syndrome". During medical school, many first year students go through a phase in which they are convinced that they have the diseases that they are studying. Hearing about a medical problem frequently enough can make you believe that you have the problem or even actually lead to the problem if the power of suggestion and the mind-body connection happens to be strong enough for that disease. And the mind is definitely connected with that part of the body. So the question is how many men who didn't really have ED ended up being convinced that they actually had it after watching the commercials?

A second potential side effect is displacing other possible treatments for ED, especially those focused on lifestyle changes. Eating a healthy diet, getting enough physical activity, decreasing stress, practicing relaxation techniques, improving your sleep, and losing weight can often help with ED. Of course, popping a pill can seem easier and quicker than these other approaches but may not be the best longer-term solution and should not be the first option. Taking medications can help overlook or even mask serious conditions causing the ED such as obesity, diabetes, or cardiovascular disease. Ultimately, treating the underlying cause of ED is usually safer and can be more effective.

A third side effect has been what was originally an ED drug has now become for many a PED, as in a performance enhancing drug, which, in turn, could be artificially raising expectations. Now a number of men who do not suffer from ED use Viagra (or Cialis or Levitra) as a sex aid, sort of like "juicing" for sex. It's a bit like major league baseball when it moved into the 1990's PED/steroids era.  The definition of success and entertainment changed. Suddenly 20 to 40 home runs a season was not enough. Getting 60 or even 70 home runs became more of the norm. While they don't keep the same type of statistics for sex as they do for major league baseball (otherwise you may not want to see your batting average or on-base percentage), one has to wonder how using such sex PEDs may have altered the perceptions, dynamics, psychology, emotional aspects, and health of sex. Humans are by nature imperfect. You aren't going to hit a home run every time you get up to bat. Sometimes, you swing and miss or hit a foul ball or bunt. You may even trip while running the bases. A healthy relationship will accommodate and even embrace such imperfections and foibles. However, anything that can result in an erection lasting for 3 hours and 59 minutes and technically still be OK, could really change how people interact with each other and feel about themselves.

Then, there's how Viagra altered the pharmaceutical industry, becoming basically its first blockbuster "lifestyle" medication. Some have wondered how much Viagra's success has shifted effort and resources away from the development of other medications such as those for infectious diseases and cancer.

With Viagra about to reach its 20th birthday, there's no question that this little blue pill has already had a big impact. Soon sildanefil will become significantly cheaper and more available. In fact, as Billy Perrigo reported for Time, it will be sold over-the-counter in the United Kingdom. What can only imagine what the next 20 years may bring.