Lipitor is the number one selling prescription medication in the world. And its maker, Pfizer, is spending millions to keep it that way.

Consumer Reports takes a closer look at the ads that may leave you thinking Lipitor is the only cholesterol-lowering drug you can trust.

TV commercial: "Inventor of the Jarvik Artificial Heart, Dr. Robert Jarvik: ‘Now I trust my heart to Lipitor,’"

Pfizer, the maker of Lipitor, spent well over $100 million on ads like this in the first nine months of last year. Gayle Williams, Consumer Reports' deputy health editor, says that's because statins are a multi-billion dollar business.

"Around 20 million Americans take statins to lower their cholesterol,” Williams said. “Three of these are available as generics, and Pfizer wants to hang on to its market share.”

Americans spent more than $6.5 billion on Lipitor in 2006 alone.

The three generic statins — Simvastatin, Pravastatin, and Lovastatin — cost far less.

"Lipitor is a highly effective drug and it's one good choice for people who have high levels of LDL cholesterol, or who've had a heart attack, or who have acute coronary syndrome,” explained Williams. “However, the vast majority of people can get the same protection from a generic statin at less than half the cost."

And although Lipitor's Web site makes a point of saying there is "no generic form of Lipitor," there will be in two years when its patent expires.

No doubt that's another reason Pfizer is spending big bucks now to drill its brand name into your head.

Consumer Reports says generic drugs are chemical twins of brand-name drugs whose patents have expired.

You can get more information about cost-saving generic statins from Consumer Reports' free service, Best Buy Drugs.