Pfizer is planning to sell cholesterol drug Lipitor directly to patients at generic prices once the company loses patent protection, in an attempt to retain sales.

Since its 1997 launch, Lipitor has earned Pfizer in excess of $81bn. However, the drug’s patent expires on 30 November, after which patients are expected to flock towards cheaper generic versions of the drug.

In an agreement with Diplomat Specialty Pharmacy, patients will be able to order the drug directly through them and receive via the post, reports the Wall Street Journal.

The patent expiry of Lipitor has long been a concern for Pfizer, with the company looking to expand into emerging markets in the hope that patients will pay for a branded version of the drug rather than a generic one.