Matt Rourke/Associated Press

Regulators have given their blessing for Express Scripts to buy Medco Health Solutions, the final hurdle in a $29 billion deal creating the nation’s largest pharmacy benefits provider.

The Federal Trade Commission voted 3 to 1 to approve the acquisition on Monday, ending an eight-month inquiry into whether the deal would stifle competition in the pharmacy benefits industry. The agency’s approval is the closing of one of the largest deals of 2011, and one that was the subject of a lot of antitrust concerns.

“The acquisition of Medco by Express Scripts will likely not change these dynamics: the merging parties are not particularly close competitors, the market today is not conducive to coordinated interaction, and there is little risk of the merged company exercising monopsony power,” the commission’s majority said in a statement.

In July, Express Scripts offered $28.80 a share in cash and 0.81 of an Express Scripts share for each Medco share. Shareholders of both companies had approved the deal. On Monday, the companies announced the deal was completed.

“Our merger is exactly what the country needs now,” George Paz, chief executive of Express Scripts, said in a statement. “It represents the next chapter of our mission to lower costs, drive out waste in health care and improve patient health.”

A focus of the commission’s inquiry was whether patients covered by the pharmacy benefits industry, which has only one other major independent player, CVS Caremark, would be harmed by the creation of a mega-provider. But the commission’s majority found that the pharmacy benefits industry was “characterized by numerous, vigorous competitors who are expanding and winning business from traditional market leaders.”

“This was not an easy decision,” the three commissioners voting to approve the deal said in a statement. But the commissioners noted that few of the dangers of a merger between pharmacy benefits giants — rising prices on specialty drugs and anticompetitive bidding processes with retailers — were likely to pan out.

The sole dissenter in the F.T.C.’s vote, Commissioner Julie Brill, said in a separate statement that the merger would create a “duopoly with few efficiencies in a market with high entry barriers — something no court has ever approved.”