Look Back at Evolution of the Little Blue Pill

Fifteen years ago, men who were suffering from impotence received a beacon of hope in the form of a little blue pill.
Wednesday marks the 15th anniversary of Viagra's FDA approval in the United States. Viagra currently holds 45% of the sexual dysfunction market share, with competitor Cialis in close second, according to industry researcher IMS Health. There were 8 million Viagra prescriptions written in 2012 with total sales of about $2 billion.
But how did a drug that was originally tested for the treatment of heart problems end up in bedrooms across America? Take a look back at Viagra's history.