WASHINGTON -- A total of five Republican senators are now opposed to the proposed GOP health bill. It would take only three defections to Democrats opposing the bill to sink the measure.

Sen. Dean Heller of Nevada is the latest Republican to say he wouldn't support the GOP health bill without changes. Several other Republican senators have declined to commit to the latest GOP plan for overhauling President Barack Obama's signature health care law.

The measure resembles the House bill that the nonpartisan Congressional Budget Office says would mean 23 million additional uninsured people within a decade.

Senate Majority Leader Mitch McConnell has said he's willing to alter the measure to attract support. He's promised plenty of back-room bargaining as he tries pushing a final package through the Senate next week.