He leaves after overseeing the recent $67 billion acquisition of Wyeth, highlighting the huge personal pressure of the position.
“The combination of meeting the requirements of our many stakeholders around the world and the 24/7 nature of my responsibilities, has made this period extremely demanding on me personally,” he said.
“I am excited at the opportunity to recharge my batteries, spend some rare time with my family and prepare for the next challenge in my career.”
Pfizer’s head of global biopharmaceutical operations Ian Read will succeed him as CEO. Mr Read will also take on the post of President with a new non-executive chairman to be elected from the company’s current membership in the next two weeks.