Congressional Democrats' intensifying efforts to pay for their healthcare overhaul and provide more relief for consumers are threatening to unravel a White House deal with the pharmaceutical industry and turn one of Washington's most powerful lobbies against the legislation. Drug makers, which have already spent $110 million lobbying Congress this year, are preparing to make a stand in the Senate, where Majority Leader Harry Reid is working to unveil a healthcare bill this week. And senior administration officials, including White House Chief of Staff Rahm Emanuel, are warning members of Congress not to antagonize the deep-pocketed industry at a time when a major victory appears to be within reach, according to Democratic aides.