MADRID, July 8 (Reuters) - The Grifols family and Canadian fund Brookfield are in talks to launch a takeover bid for Spanish drugmaker Grifols that could be worth around 5.5 billion euros ($5.95 billion), business newspaper Cinco Dias reported on Sunday, citing unnamed people familiar with the plans.

According to the report, Grifols' board held an extraordinary meeting over the weekend to study a preliminary offer presented by the founding family, which currently controls about 30% of the company's shares.

The family's aim is to gain access to the company's books in order to make a final offer in the coming weeks, the report said, adding that Lazard was the sole financial advisor to both parties.

Neither Grifols nor Brookfield were immediately available for comment on Monday.

The company's main shareholders - after the descendants of three brothers who took the company from a small family-owned laboratory in Barcelona to a global player in the plasma derivatives business - include the funds Capital, Blackrock, Europacific and Rokos Global.

Since early January, short-seller fund Gotham City Research has released several reports accusing Grifols of overstating earnings and understating debt. The firm's market value has shed several billion euros since then.

Following Gotham City's reports, Grifols announced governance changes and revised its reported leverage higher after market supervisor CNMV required that it change its calculations.

Last week, Grifols appointed Rahul Srinivasan as chief financial officer in a management reshuffle and Scranton Enterprises, an entity tied to the Grifols family, reached an agreement with a private investor to refinance 377 million euros of debt in one of its units. ($1 = 0.9240 euros) (Reporting by David Latona; Editing by)