The company has approached a number of undisclosed agencies and is drawing up a shortlist to pitch for the account in three weeks' time.
AstraZeneca's marketing team will be managing the review in-house.
Once appointed, the agency will be responsible for developing websites and digital communications for the company's pharmaceutical brands in the UK.
AstraZeneca currently uses several different UK agencies to handle digital communications. However, industry insiders suggest it is looking to consolidate its online communications and increase its levels of digital activity.
The company creates pharmaceutical products across a range of medical needs, from cancer to neuroscience. In 2005, it reported global sales of more than $23 billion.
AstraZeneca was unavailable to comment on the review.