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13. Merck
Fortune rank: 13
2008 profit: $7.81 Billion
Merck, the world's No. 2 drugmaker behind Pfizer, had a tough year as it lost patent protection on its blockbuster osteoporosis drug Fosamax and faced questions from the FDA on the safety of cholesterol drug Vytorin.

Though 2008 profits climbed 138% over the prior year, the increase came mostly from easy comparisons to 2007 when Merck settled Vioxx lawsuits.

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Last updated April 20 2009: 11:09 AM ET
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