Jeremy Hobson: Well this week is a big week for drugmaker Pfizer. It’s blockbuster cholesterol drug Lipitor goes “off-patent.” That means a lot more competition for the best-selling drug in history.

But as Gregory Warner reports from the Marketplace health desk at WHYY in Philadelphia, Pfizer is trying a new strategy to hang onto customers.

Gregory Warner: Drug companies usually squeeze every last sale that they can out of a drug until it goes off patent. And then, the generic manufacturers gradually take over the business.

Mike McCaughan: Most brand name companies, when they lost their patent protection, would essentially walk away from the brand.

Mike McCaughan writes the online trade publication RPM Report. He says Pfizer can’t afford to walk away from the best selling drug of all time. So the company has partnered with a pharmacy in Michigan to sell Lipitor by mail order at generic prices.

McCaughan: They’re going to make it as easy as possible for you to buy brand name Pfizer and not pay any more than you would for a generic drug.

Pfizer is banking on consumers willing to buy drugs online, and a lot of Lipitor loyalty. If the strategy works, other drug companies could follow. There are a lot of blockbusters with patents expiring. Next up this Spring is Plavix, the country’s third best selling drug.

In Philadelphia, I’m Gregory Warner for Marketplace.