WASHINGTON • Dr. Donald Berwick, the Harvard pediatrician whom President Barack Obama tapped to head the Medicare and Medicaid programs, will step down next week in the face of staunch Republican opposition to his permanent appointment to implement Obama's health care law.

Berwick, a longtime advocate for patient safety, has been widely hailed by doctors, hospital officials and other health care leaders for his trailblazing work to improve the quality and efficiency of American health care.

But Republican lawmakers outraged at the new law immediately attacked Berwick when the president nominated him in 2010 to head the Centers for Medicare and Medicaid Services, which oversees government health care programs that insure close to 100 million Americans.

In response, Obama circumvented the Senate confirmation process, appointing Berwick while Congress was in recess in July 2010.

The move, which hardened GOP opposition, meant Berwick had to step down by the end of this year.

"Don has led the agency as we have launched exciting new programs that are saving money, fighting fraud, transforming our health care delivery system, providing new benefits to people with Medicare, holding insurance companies accountable to consumers, and working to establish Affordable Insurance Exchanges," Secretary of Health and Human Services Kathleen Sebelius told the department Wednesday in announcing Berwick's departure, which will be effective Dec. 2.

To replace Berwick, the president plans to nominate Marilyn Tavenner, a former nurse and Virginia secretary of Health and Human Resources.

"Don Berwick did outstanding work" in the assignment, said deputy White House press secretary Jamie Smith. "It's unfortunate that a small group of senators obstructed his nomination, putting political interests above the best interests of the American people."

Smith said that Tavenner "is an experienced leader who will build on this incredible record of accomplishment and make Medicare and Medicaid even stronger, and we hope that the Senate will act quickly to confirm her."