WASHINGTON — Legislation to give additional months of unemployment benefits to people who have been out of a job for more than half a year cleared a key hurdle Tuesday that guarantees it will soon pass the Senate.

The sweeping bill also would prevent doctors from absorbing a crippling cut in Medicare payments and extends health insurance subsidies for the unemployed through December. It would add $132 billion to the budget deficit over the next year and a half.

Eight Republicans voted with Democrats to defeat a GOP filibuster of the measure, setting up a final vote as soon as later on Tuesday.

The measure illustrates the great extent to which direct help for the jobless and the poor makes up a large portion of Democrats’ election-year agenda on jobs — and that it threatens to squeeze out other items on that agenda amid concerns about a budget deficit projected at a record $1.6 trillion this year.

The bill also provides the annual extension of $26 billion worth of tax breaks for businesses and individuals that are popular with senators in both parties.

The $66 billion cost of providing the extended unemployment checks is added directly to a budget deficit expected to hit $1.6 trillion this year. In states with the highest jobless rates people are eligible to receive benefits for up to 99 weeks. A 65 percent health insurance subsidy for the unemployed under the COBRA program adds about another $10 billion. Federal cash to help states with Medicaid adds about $25 billion more.