When Merck & Co. pulled its big-selling painkiller Vioxx off the market in September, Chief Executive Raymond Gilmartin said the company was "really putting patient safety first." He said the study findings prompting the withdrawal, which tied Vioxx to heart-attack and stroke risk, were "unexpected."

But internal Merck e-mails and marketing materials as well as interviews with outside scientists show that the company fought forcefully for years to keep safety concerns from destroying the drug's commercial prospects...

As academic researchers increasingly raised questions about Vioxx's heart safety, the company struck back hard. It even sued one Spanish pharmacologist, trying unsuccessfully to force a correction of an article he wrote. In another case, it warned that a Stanford University researcher would "flame out" unless he stopped giving "anti-Merck" lectures, according to a letter of complaint written to Merck by a Stanford professor. A company training document listed potential tough questions about Vioxx and said in capital letters, "DODGE!"

The revelations shed new light on the interplay between marketing and science at Merck as bad news piled up about a blockbuster drug used by some 20 million Americans. Amid growing danger signs, Merck fought a rearguard action for 4½ years, clinging to a hope that somehow Vioxx's safety could be confirmed -- even though its research chief had already privately acknowledged its risks...

A Merck internal marketing document reviewed by The Wall Street Journal, addressed to "all field personnel with responsibility for Vioxx," provided an "obstacle handling guide." If a doctor said he was worried that Vioxx might raise the risk of a heart attack, he was to be told that the drug "would not be expected to demonstrate reductions" in heart attacks or other cardiovascular problems and that it was "not a substitute for aspirin." This wasn't a direct answer.

One training document is titled "Dodge Ball Vioxx" and consists of 16 pages. Each of the first 12 pages lists one "obstacle," apparently representing statements that might be made by a doctor. Among them are, "I am concerned about the cardiovascular effects of Vioxx" and "The competition has been in my office telling me that the incidence of heart attacks is greater with Vioxx than Celebrex." The final four pages each contain a single word in capital letters: "DODGE!"...

Merck also went on the offensive against academic researchers who began to question Vioxx's safety. Gurkirpal Singh of Stanford University, a prominent Cox-2 expert who was giving lectures sponsored by Merck and other companies, says he pressed Merck repeatedly for more cardiovascular safety data. When Merck refused, Dr. Singh added a slide to his presentations that showed a man -- representing the missing data -- hiding under a blanket. "This was the first time they didn't answer my questions," he says. "With Vigor, suddenly it was a clampdown."