Washington ? Republicans eased their Medicare prescription drug bill over its first House hurdle Tuesday night, rejecting Democratic claims it would leave seniors worse off and erode the foundation of the 38-year-old health care program.

The vote in the House Ways and Means Committee, 25-15, largely along party lines, came after Republicans defeated Democratic attempts to reduce the clout that private industry would gain within a modernized Medicare system.

“While we do want to provide this very important new benefit we want to make sure that Medicare is sustainable for today’s seniors, but just as well for tomorrow’s,” California Rep. Bill Thomas, the committee chairman, said of the measure that combines a new drug benefit with a new managed care option for overall health coverage.

But New York Rep. Charles Rangel, the senior Democrat on the committee, said that while Republicans touted the prescription drug coverage, “the price of that benefit is the end of Medicare as we know it. If this bill becomes law, it will start a time bomb that will go off in 2010 and end the guarantee of affordable coverage under Medicare.”

The House panel struggled through hours of partisan clashes at the same time officials in the Senate worked on last-minute revisions in a bipartisan measure expected to face its first test votes today.

Congressional budget analysts reported that bill would result in monthly premiums for drug coverage of $41. But Republican and Democratic officials alike said that was merely a mistake, and that the legislation would offer insurance at a monthly cost of $35, as long promised.

The House bill and the companion Senate measure are both designed to provide prescription drug benefits for senior citizens, to be offered by private insurance companies and subsidized by the government. In addition, the legislation would offer a new managed care option for Medicare.