The Anglo-Swedish firm wants to investigate 'fresh ways of communicating' its neuroscience brands, said AZ global director of product PR Margaret Morgan.
Cohn & Wolfe, Porter Novelli, Chandler Chicco Agency and Red Door Communications have already presented credentials.
Morgan told PRWeek: 'We may see some more agencies. Things are exploratory at this stage.'
Seroquel is a fast-growing treatment for schizophrenia, while Cerovive is a pre-launch treatment for strokes.
Seroquel is currently promoted on a global basis by Shire Health International; Fleishman-Hillard's healthcare division (formerly CPR Worldwide) handles Cerovive globally.
'These agencies shouldn't feel threatened. This doesn't necessarily mean one or both of these agencies will be replaced - we may add to our portfolio,' Morgan said.
AZ announced last week that it plans to press ahead with further clinical trials of Cerovive; it is to file regulatory submissions in the second half of next year.
Data from a trial involving more than 1,700 patients, unveiled last week, showed Cerovive achieved 'statistical significance' in reducing disability after a major stroke.
Agencies with country-specific remits, such as Edelman (Seroquel in the US) and Munro & Forster Communications (Seroquel in the UK), are not affected by the review.
Morgan, AZ global PR manager for neuroscience Louise Marland and brand marketing teams are co-ordinating the review from AZ's Cheshire offices.