The measure would insure about 50,000 fewer people under Medicaid, a change that would need a federal approval that has not been given for any other state. Republican lawmakers argue that and other restrictions are essential to controlling long-term costs, but say their plan will still cover the state's neediest.
The fast-moving measure still needs another vote from the state Senate before it goes to the governor's desk, but leaders there said they support it.
Demonstrators carrying signs like "Respect democracy, our vote matters" stationed themselves outside the chamber along with four religious leaders who blocked the doors singing protest songs.
The law that passed last November with 53 percent of the vote would fully expand Medicaid to people making up to 138 percent of the poverty line, or about 150,000 low-income people.
Lawmakers' version scales that back to 100 percent of the line; people who make more could get coverage by buying subsidized insurance on the federal exchanges. The bill also adds work requirements and spending caps. The state would pay millions to roll out the more-limited program on April 1, the date approved by voters.
Some opponents were heartened by changes to the bill Friday, including a provision that would expand Medicaid everyone covered by the November vote if the U.S. government doesn't approve the more-limited plan.
Rev. David Nichols remained skeptical. He protested because he sees people in his congregation working two or three part-time jobs but can't afford health care. "We have to speak for the voiceless, we have to speak for those that are being shut out and left behind," said Nichols.
Counter-protesters who argued the state can't afford full Medicaid expansion also stationed themselves nearby, sometimes singing their own songs like "America the Beautiful."
They support the plan that's passing quickly through the GOP-dominated Utah Legislature. About three-quarters of the chamber voted in favor, though a few Republicans joined Democrats to oppose it.
"Were doing the very best we can and I think we've got a great solution here," said Senate President Stuart Adams, whose chamber is expected to vote Monday.
The House changes include a plan to revert back to much of what the voters passed if the federal waivers aren't approved, an improvement for many Democrats who worry the waivers might not come through, said Sen. Derek Kitchen.
The Group Utah Decides, though, nevertheless called the vote "a shocking display of disrespect for Utah voters."
Around the country, a number of largely conservative state leaders have changed or brushed aside voter-approved ballot initiatives in recent years, including Medicaid expansion in Maine that was initially blocked by the former Republican governor.
Two other Republican-leaning states also passed similar expansions in November. The roll-out appears on track in Nebraska, though in Idaho protesters have rallied after some lawmakers suggested adding work requirements.