The vote, 217-214, was almost entirely along party lines, and sent the measure to an uncertain fate in the Senate.
Earlier, Democrats walked off the floor of the House in protest as Republicans began pushing toward passage of the bill.
"It's a sham, it's a hoax, it's a political fig-leaf," said House Minority Leader Richard Gephardt, D-Mo., who complained that Democrats were not permitted by the GOP majority to offer their alternative plan.
In addition to the walkout, Democrats began forcing a series of procedural votes to delay what appeared to be inevitable passage of the Republican plan.
"Older Americans deserve financial security and health security. Our plan would ensure both of them," House Speaker Dennis Hastert, R-Ill., said Tuesday as the GOP high command counted votes in advance of Wednesday's showdown. "When it comes to prescription drug coverage, the time for politics is over and the time for progress is now."
But Democrats said politics and Republicans' fear of a backlash from senior citizens was driving the GOP to propose a sham bill that would principally benefit the pharmaceutical industry. "Not only is it empty promises, it is empty pill jars," Rep. Patrick Kennedy, D-R.I., jabbed, holding an empty vial aloft to dramatize his point.
President Clinton joined the GOP-bashing, telling an audience Tuesday night that Republicans were afraid to let a costlier and more generous Democratic plan come to a vote. "Why?" he asked rhetorically. "Because it might pass in an election year. Because they're just five seats in the majority and they figure there might be six or seven of them that might figure out that the voters back home may actually look at the vote."
The scheduled vote capped a brief but intense struggle over the issue likely to resonate into the fall campaign, in which Democrats are mounting a major effort to overturn the narrow GOP majority in the House.
The Republican bill envisions a blend of private insurance companies and federal subsidies to spread prescription drug coverage nationwide to any Medicare-eligible senior citizen who wants it. The bill, estimated to cost about $40 billion over five years, includes subsidies for low-income seniors as well as those with high drug expenses.
The Democratic proposal, with a price tag nearly double the GOP plan, calls for a program in which the government establishes a uniform drug benefit to be made available nationwide. It, too, contains subsidies for the poor, and more generous benefits for seniors with high drug costs than Republicans prvide.
Beneath the debate over policy differences, though, lie competing political calculations.
Republicans, cautioned by their pollster that passing legislation is a "political imperative," pushed the bill through committee last week on a party-line vote and expressed confidence they could do the same on the House floor.
Democrats, determined to attract senior citizen support as part of their campaign to win the House this fall, labored to hold defections to a minimum, part of a strategy to deny GOP claims that their measure was a bipartisan solution to a problem vital to 39 million senior citizens.
In the meantime, Democrats turned a basement room in the Capitol into a mock pharmacy, and arranged for a succession of lawmakers to be available around the clock for talk radio programs and other appearances designed to underscore their opposition to the GOP bill.
Republicans countered with some political theater of their own.
They touted their proposal at a ceremony on the steps outside the Capitol on Tuesday, with entertainment provided by a retirement-age barbershop quartet.
Hastert and other supporters of the bill walked to the microphones serenaded to the tune of Happy Days Are Here Again, a virtual anthem for Democrats for more than a generation.