DEERFIELD, Ill. — Walgreen Co. has received all of the necessary regulatory approvals to complete the initial phase of its takeover of Alliance Boots PLC.

Walgreen Co. has received all of the necessary regulatory approvals to complete the initial phase of its takeover of Alliance Boots PLC.

Under the terms of the deal announced earlier this summer, Walgreens has paid $4 billion in cash and 83.4 million shares of its common stock in exchange for a 45% stake in Alliance Boots.

The deal makes Alliance Santé Participations S.A., the family trust operated by Alliance Boots executive chairman Stefano Pessina, Walgreens’ largest ­shareholder.

Pessina says the trust expects to hold the stock for the long term.

Under the original terms of the deal between Walgreens and Allinace Boots, Walgreens now has the option to buy the remaining 55% of Alliance Boots over the next three years.

The completion of the initial phase of the deal also saw Pessina and KKR & Co. general partner Dominic Murphy join Walgreens’ board of directors.

Meanwhile, four Walgreens executives have become members of the Alliance Boots board of directors.