As Lipitor Patent Expires, Pfizer Fights to Keep Users

The biggest-selling drug of all time—Lipitor—is now available for production in generic form as Pfizer's patent on the cholesterol-lowering pill expired today, reports AFP. It's such a huge money-maker for Pfizer, however, that the company is rolling out all kinds of discounts and incentives to keep its 9 million users from switching, notes AP. Lipitor currently costs about $120 per month, and that should steadily decrease.

Separately, American pharma company Watson Pharmaceuticals will sell an "authorized" generic version of atorvastatin calcium in tandem with Pfizer, and the two will share sales for five years. A company based in India, Ranbaxy, also plans a generic version in the coming months but has yet to get approval from the FDA. (More Lipitor stories.)