By DIEDTRA HENDERSON, AP Science Writer

WASHINGTON - The American public is "virtually defenseless" if another medication such as Vioxx proves to be unsafe after it is approved for sale, a government drug safety reviewer told a congressional committee Thursday.

"I would argue that the FDA as currently configured is incapable of protecting America against another Vioxx," said David Graham, who warned that the arthritis drug had been linked to an increased risk of heart attack and stroke.

He told the Senate Finance Committee that there were at least five other drugs on the market today that should be looked at seriously to see whether they should remain there. He cited the acne drug Accutane, the weight loss drug Meridia, the anti-cholesterol drug Crestor, the pain reliever Bextra, and the asthma drug Serevent.

AstraZeneca Pharmaceuticals, maker of Crestor, said it was confident that the drug was safe. "To date, the FDA has not given us any indication of a major concern regarding Crestor," said spokeswoman Emily Denney.

Makers of the other drugs did not immediately return calls for comment.

Vioxx's maker, Merck & Co. pulled the drug from the market on Sept. 30 after a study indicated the popular painkiller doubled the risk of heart attacks and stroke when taken for longer than 18 months.

Raymond V. Gilmartin, the company president, said in prepared testimony that Merck acted within four days of learning about the risk.

"Given the availability of alternative therapies and the questions raised by the data withdrawing Vioxx was consistent with an ethic that has driven Merck actions and decisions for more than 100 years," he said.

Gilmartin also said the company was surprised by the cardiovascular risk because it differed from past clinical trials. "My wife was a user of Vioxx until the day we withdrew it from the marketplace," he said.

The Food and Drug Administration has defended its actions regarding Vioxx. In a statement issued late Wednesday, the agency cited its "well-documented and long-standing commitment to openness and transparency in its review of marketed drugs."

However, Sen. Charles Grassley, R-Iowa, who chaired the hearing, suggested that an independent board of drug safety might be needed to ensure the safety of medications after they're approved for the market.

"Consumers should not have to second-guess the safety of what's in their medicine cabinet," he said.

Graham told the committee that research indicated that Vioxx caused up to 160,000 heart attacks and strokes.

"If we were talking about Florida or Pennsylvania, 1 percent of the entire state population would have been affected," he said. "I'm sorry to say Sen. Grassley, but 67 percent of the citizens of Des Moines would be affected and, what's worse — the entire population of every other city in the state of Iowa."

Graham said his research helped to coax the FDA to withdraw a number of drugs including Fen-phen, a weight loss drug, Lotronex, Baycol and Rezulin. "During my career I have recommended the market withdrawal of 12 drugs," he said. "Only two of these remain on the market today."

At the same time, though, he questioned the agency's commitment to removing unsafe drugs from the market, since it would call into question their earlier approval.

Sen. Jeff Bingaman, D-New Mexico, said the problem was within the FDA's own culture.

"The culture within the FDA, being one where the pharmaceutical industry, which the FDA is supposed to regulate, is seen by the FDA as its client instead," he said.

He called on President Bush to appoint a new head for the agency. Lester Crawford has been acting commissioner of the agency.

In the FDA statement, Crawford said the FDA initiated and paid for reviews of Vioxx and antidepressants after those drugs had hit the market. "That is evidence the system is working," Crawford said.

Critics contend the agency ignored risks in both instances, then intimidated its own reviewers when they pointed to safety concerns.

In October, the FDA ordered that all antidepressants carry warnings that they "increase the risk of suicidal thinking and behavior" in children who take them.

The FDA's statement disturbed lawyer Andy Birchfield, who is evaluating thousands of potential cases against Merck on behalf of injured patients.

"How can they see that type of problem and look back and say 'We did everything right'?" Birchfield said. "When they're not willing to recognize mistakes, we have no hope for them voluntarily taking measures to correct the situation."

Crawford's statement did not mention Graham by name, but suggested that the reviewer was a maverick who did not follow agency protocol.

Graham was lead author on a research project that studied the records of almost 1.4 million Kaiser Permanente patients, including 40,405 treated with Pfizer's Celebrex and 26,748 treated with Vioxx. The study found that high doses of Vioxx tripled risks of heart attacks and sudden cardiac death.

Vioxx was responsible for an additional 27,785 deaths from heart ailments from 1999 to 2003, Graham concluded.

He has told congressional investigators that superiors pressured him to soften his conclusions. Crawford said in his statement that the reviewer "voluntarily chose to revise his conclusions, and he did so, in his own words, "without compromising my deeply held convictions.'"