The emerging Senate bill, like the one approved narrowly by the House in early May, would end Medicaid as an open-ended entitlement program and replace it with capped payments to states, Republicans said. But starting in 2025, payments to the states would grow more slowly than those envisioned in the House bill.
Republican senators from states that have been hit hard by the opioid drug crisis have tried to cushion the Medicaid blow with a separate funding stream of $45 billion over 10 years for substance abuse treatment and prevention costs, now covered by the expansion of Medicaid under the Affordable Care Act.
But that, too, is running into opposition from conservatives. They have been tussling over the issue with moderate Republican senators like Rob Portman of Ohio, Shelley Moore Capito of West Virginia and Susan Collins of Maine.
Without some opioid funding, Mr. Portman cannot vote for the bill, he said, adding, “Any replacement is going to have to do something to address this opioid crisis that is gripping our country.”
Republicans hold 52 seats in the Senate and can afford to lose only two of their members if they hope to pass the bill, which is opposed by all Democrats and the two independents.
Two Democratic senators from states plagued by opioid addiction, Bob Casey of Pennsylvania and Joe Manchin III of West Virginia, said the Republican proposal for federal grants would not come close to mitigating the harm caused by the bill’s Medicaid cuts, pushed just as overdose deaths are soaring. From 2005 to 2014, according to the latest data available, opioid-related hospital visits increased nearly 65 percent, to 1.27 million emergency room visits or inpatient stays a year.
While the proposed money for drug abuse treatment is relatively modest compared with spending for other items like Medicaid and premium tax credits, without it, hundreds of thousands of addicts would go without treatment, advocates say. The issue holds outsize political importance for senators like Mr. Portman, who has made advocacy for treatment legislation a calling card with voters at home.
“The opioid issue has been a particular concern of mine and has been for years,” said Mr. Portman, who has been leading the efforts with Senator Capito. “The reality is we have the worst drug crisis that our country’s ever faced, and it’s being driven by opioids.”
Senator John Barrasso, Republican of Wyoming, who serves on a group shaping the final bill, said: “We need to address the opioid crisis in America. I want us to find a bipartisan solution with adequate funding.”
But Republican leaders would not commit to Mr. Portman’s proposal.
The Medicaid and opioid issues are far from the only ones dividing Republican senators, who have been kept largely in the dark about a bill they are supposed to finally see on Thursday. Republican leaders are determined to keep their seven-year promise to unravel President Barack Obama’s signature health care law, but the near unanimity they need on a replacement is proving elusive.
The House bill would allow per-capita Medicaid payments to states to grow along with the prices of medical goods and services, starting in 2020, with an extra allowance for older Americans and people with disabilities. Senator Toomey and several other conservatives have been pushing for a slower growth rate, to reflect increases in the overall Consumer Price Index, starting in 2025. Medical prices have historically grown faster than the overall index.
“I think that’s a problem,” Senator Capito of West Virginia told the website Axios, reflecting the misgivings of a state that relies heavily on the program. “I think that sort of defeats the purpose of keeping people on, and at a level at which the program can be sustained.”
Several Republican senators, including Orrin G. Hatch of Utah, the chairman of the Finance Committee, have indicated they would like to exempt disabled children from the caps.
Senator Collins’s concerns cover almost the entire landscape of Republican problems: the loss of care for Medicaid recipients, the worries of states with especially high health care costs, and money for opioid treatment (8 percent of all births in her state, Maine, were to addicted mothers last year, she said). Then there are her complaints about the process.
“First, we haven’t seen the bill,” Ms. Collins said. “Second, it has yet to receive a score from the Congressional Budget Office. And third is the process we are using.”
That process — an arcane budget procedure that Republicans denounced when Democrats used it to pass just a small part of the Affordable Care Act — could make some provisions vulnerable to Democratic challenges to the bill. Not knowing which provisions will stay and which could be removed on the Senate floor makes evaluating the substance of the bill that much harder.
Republican aides speculated that the restrictions on the growth of Medicaid, among other issues, could be altered later by Senate Republican leaders, in a bid to pick up support from the moderates.
A bill this large with so much in flux days before it is to receive a vote on the floor is largely without precedent in the Senate.
Senior Republican senators said six weeks ago that they would start afresh in writing a bill to undo Mr. Obama’s health care law, but the legislation they are developing is similar in many respects to the bill passed by the House.
The Senate bill would eliminate penalties for people who do not have insurance and larger employers who do not offer it to employees — eviscerating the individual and employer mandates that were hallmarks of the Affordable Care Act. The Senate bill, like the House measure, would provide billions of dollars to states to help stabilize insurance markets, which Republicans say are tottering in many states.
The Senate bill would also allow states to opt out of many federal insurance standards. Republican leaders said they wanted to protect people with pre-existing conditions, but it was not immediately clear how they would do so.
Democrats stepped up their protests over the secrecy of the bill-writing process on Tuesday, and some Republicans chimed in. Senator Mike Lee, Republican of Utah, was a member of a health care working group formed by Senator Mitch McConnell of Kentucky, the majority leader, but even he was vexed by the process.
“It has become increasingly apparent in the last few days that even though we thought we were going to be in charge of writing a bill within this working group, it’s not being written by us,” Mr. Lee said in a video on Facebook. “It’s apparently being written by a small handful of staffers for members of the Republican leadership in the Senate. So if you’re frustrated by the lack of transparency in this process, I share your frustration.”