AstraZeneca and the rise of cheap generic versions of popular medicines like Lipitor and Zocor, drug companies have fled the field.

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Lipitor could see its sales almost entirely eroded by cheap generic knockoffs when a key patent expires four years from now.

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The price disparity between the two drugs will only increase in 2006, when Pravachol loses patent protection. (Lipitor does not lose patent protection until 2010.) At that point, cheap generic Pravachol copycats are likely to flood the market.

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The big exception, he says, are statin medications like Lipitor, Crestor, Zocor, and Pravachol, most of which are now cheap and generic and have been shown to reduce heart attacks and deaths in big studies, and which are among the most commonly prescribed medicines.

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