Shares of Merck & Co. plunged more than 10 percent yesterday after a news report said documents showed the pharmaceutical giant hid or denied evidence for years that its blockbuster arthritis drug Vioxx causes heart problems.

Plaintiffs' attorneys stepped up pressure on Merck on cases related to its withdrawal of Vioxx, the anti-inflammatory drug, sending the US drugmaker's shares plummeting again on Monday.

Senate investigators examining Merck's recall of its Vioxx painkiller have interviewed an Alabama lawyer whose firm has filed 58 lawsuits against the company on

Shares of Merck & Co. plunged again Monday after a news report suggested the drug maker attempted to keep safety worries from hurting the prospects of Vioxx before the company finally recalled the painkiller.

Amid growing concern about litigation over Vioxx, the painkiller yanked off the market, Merck & Co. shares fell nearly 10% and Standard & Poor's Rating Services placed the company's triple-A corporate credit and senior unsecured debt rating on watch with negative implications.

Plaintiffs' attorneys stepped up pressure on Merck on cases related to its withdrawal of Vioxx, the anti-inflammatory drug, sending the US drugmaker's shares plummeting again.

Shares of Merck & Co. plunged again after a news report suggested the drug maker attempted to keep safety worries from hurting the prospects of Vioxx before the company finally recalled the painkiller.

Surveying the wreckage of the worst pharmaceutical tort litigations of the past, investors naturally want to know: Will Vioxx be the next Baycol, or Rezulin, or fen-phen? Our prediction is: yes, but bigger.

Merck's press conference was very disappointing, according to Andy Birchfield, "Instead of accepting responsibility for putting a dangerous drug on the market and keeping it there for so long, Merck spent an hour defending itself."

Lawsuits. Lawsuits. Lawsuits. And they're coming fast. The recall came after testing revealed the risk of heart attack or stroke doubled for those taking Vioxx.