President Bush's nominee to oversee the Food and Drug Administration (search) rejected claims by Senate Democrats Thursday that the agency has failed to adequately monitor prescription drug safety, but promised to create an independent board to help the agency track drugs once they're approved.

"I don't think we've been tarnished," said Lester Crawford (search), who has been acting or deputy FDA commissioner for the past three years. "... (But) I promise to you to do everything in my power to stem the tide and do the right thing."

Crawford spoke at a confirmation hearing before the Senate Committee on Health, Education, Labor and Pensions. Committee Republicans are backing the nomination, but Democrats have adopted a wait and see attitude. A vote is likely next month.

Democrats said they want Crawford to update them on the status of a drug application for RU-486 (search), often referred to as the morning-after pill. Used to prevent pregnancy, the drug is available with a prescription, but some senators say it should be available over-the-counter, as recommended by an FDA advisory committee.

The FDA regulates about $1 trillion worth of products a year and is charged with ensuring the safety and effectiveness of all drugs, medical devices, animal drugs and feed.

The agency has been under fire because of its handling of Vioxx (search), a pain killer that drug manufacturer Merck pulled from the market last September. Lawmakers also criticized the agency for failing to inspect a manufacturing plant where conditions led to the flu vaccine shortage.

"Disturbing allegations have been raised that FDA has prevented open scientific discussion of important drug-safety issues, has disregarded science that conflicts with ideology, and has retaliated against whistleblowers (search)," said Sen. Edward Kennedy, D-Mass.

Sen. Jeff Sessions, R-Ala., defended Crawford, saying he has a difficult balancing act: If the agency waits too long to approve a drug, thousands of lives can be put at risk, but if it acts too quickly, the same result is possible.

Crawford, elevated to acting FDA director a year ago, said he's "committed to addressing existing concerns regarding post-market safety of FDA-regulated products, both in medical products and food."

"I remain focused on bioterrorism and minimizing the threat of terrorist attack both through heightened food security and through the development of new medical countermeasures," he said.

Three consumer groups, in a joint letter to the committee, criticized the nomination. They contended the FDA's "high profile missteps and failure to take timely action" in protecting the public against unsafe prescription drugs raise questions about Crawford's "leadership, his ability to manage interagency conflicts and willingness to act in the best interest of consumers."

The groups, Consumers Union (search), Consumer Federation of America (search) and the U.S. Public Interest Research Group (search), focused on the FDA's response to concerns raised about Vioxx, a pain killer that drug manufacturer Merck pulled from the market last September.

Before Merck withdrew the drug, an FDA scientist had found an increased risk of heart attack and strokes in patients taking the pain killer. Also, three weeks before Merck pulled the drug, the agency approved it for use by children.

The Pharmaceutical Research and Manufacturers of America is backing Crawford's nomination.

"Dr. Crawford knows the agency and he knows it well," said Jeff Trewhitt, a spokesman for the trade group. "He responds to crises quickly and with quiet efficiency."

A day after Bush nominated him, Crawford announced his support for an independent board to oversee drug safety issues at the FDA. The board would consist of FDA employees and medical experts from other government agencies, who would be appointed by Crawford. He also promised more openness in the agency's communications with the public.

Jeannine Kenney, senior policy analyst at Consumers Union, said the FDA already has an array of advisory boards. What it needs to do is to give an already existing office more authority and more resources to track and regulate drugs once they've been approved for the market, she said.

Before coming to the FDA in 2002, Crawford served for five years as director of the Center for Food and Nutrition Policy (search) at Virginia Tech.