The company said it would cut 20 per cent of its European sales force but did not say how many jobs that will be.
Jeffrey Kindler, who became Pfizer's cheif executive last summer and chairman last month, said: "I believe we must transform the way we've done business in the past in order to be more successful in the future. Incremental evolution is not enough.
"Fundamental change is imperative - and it must happen now."
Tim Anderson, a Prudential analyst, said the company is at risk of losing 41 per cent of its sales to generic competition between 2010 and 2012, including the revenue from its top seller Lipitor.
Pfizer will close three research sites in Michigan and two manufacturing plants in New York and Nebraska. It may also sell another manufacturing site in Germany and close research sites in Japan and France.
Aside from outlining cuts, Pfizer also detailed how it would restructure its business in an effort to become more nimble and flexible.
The US commercial business will be divided into five distinct units, each with a general manager responsible for that group's performance. Two research areas are being abandoned while other research and development efforts are being consolidated.
Pfizer also pledged to interact more with potential customers such as insurers to make sure it is developing medicines they deem worthy of purchasing.
Analysts are skeptical about whether Pfizer's current and pipeline drugs can generate enough sales to compensate for revenue it stands to lose.
Pfizer said it intends to buy or collaborate with other companies to bolster its product portfolio as it attempts to improve its own research.
Pfizer reiterated it will introduce six new products a year beginning in 2011, four from its own research and two from collaborations or acquisitions.