From Crestor to Lipitor, Plavix to Zetia, drugs that made headlines for their blockbuster commercial sales when first launched may no longer have patent protection and make the news, but continue to constitute an important portion of revenue for the companies that manufacture them, providing padding for the bottom line, and in some cases, remaining top sellers. Take a look at these vital products and learn how these drugs may have decreased in blockbuster status, but continue to play an essential role in drug portfolios.