The young in spirit, usually, always want to be straight forward in the matter of desire and execution of sexual functions. Researchers always want to find a cure for weak heart. Viagra ( slidenafil) was tried in various labs. The drug was tied for curing heart and hypertension but failed in repeated experiments. After two phases of testing, researchers came to the conclusion that the drug failed to show promising results for the heart. The test subjects noted that they had the hard on as a side effect. After much deliberation, Pfizer patented Viagra in 1996 and it was approved for use in erectile dysfunction by the U.S. FDA in 1998. Sales of Viagra continue to exceed well over $1 billion per year. Bonus tip: Researchers have found that 1 milligram of sildenafil dissolved in a vase of water can make fresh cut flowers, “stand at attention” for up to a week beyond their natural life course.