NEW YORK (AP) — Express Scripts and Medco Health Solutions, the largest U.S. pharmacy benefits management companies, said Thursday they will combine in a deal worth $29.1 billion in cash and stock.

The companies manage prescription drug benefits and look for ways to cut costs for health plan sponsors and members. Combined, they handled more than 1.7 billion prescriptions in 2010 and reported almost $110 billion in revenue. The new Express Scripts Holding Inc. could use its size to negotiate bigger discounts on drug prices, although it would also have less competition than Medco and Express Scripts individually.

Express Scripts of St. Louis, will buy its rival for $71.36 per share. Medco's shareholders will get $28.80 per share in cash and 0.81 shares of Express Scripts for each share they own. That's a premium of 27.9 percent based on Medco's closing price of $55.78 Wednesday. Shares of the Franklin Lakes, N.J., company have traded between $43.45 and $65.39 in the last year.