CORRECTED-UPDATE 1-Omnicare extends PharMerica tender offer again

Jan 27 (Reuters) - Pharmacy services provider Omnicare Inc extended for the fourth time its offer to acquire shares of smaller rival PharMerica Corp.

Omnicare, which extended the offer to Feb. 17, said about 4.7 million shares, or about 16 percent of PharMerica's outstanding shares, had been tendered as on Jan. 26.

Omnicare had gone hostile with its $15-per-share bid in September 2011, after PharMerica's board had rejected its approach.

At the time, PharMerica had said the offer undervalued the company and raised doubts that any such deal would clear antitrust hurdles.

PharMerica, which has twice rejected Omnicare's $441 million offer since late August 2011, also adopted a poison pill to thwart the acquisition.

Omnicare and PharMerica are the top two companies in the pharmacy services sector, which provide drugs and softwares to nursing homes, assisted-living centers, and other long-term care facilities.

Omnicare was trading slightly down at $33.09, while those of PharMerica were down about 1 percent at $ $14.20 on Friday on the New York Stock Exchange.