HARRISBURG — A five-year, $1 billion taxpayer subsidy to help Pennsylvania doctors buy medical malpractice insurance lapsed Monday, forcing physicians to pay higher premiums unless Democrats and Republicans break an impasse over expanding a state health insurance program.

Gov. Ed Rendell supports a bill that passed the Democratic-led House on March 17 that would tie the future of the medical malpractice subsidy to approval of a $1 billion expansion of the health insurance program to cover an additional 220,000 adults who cannot afford other coverage.

But Republicans who control the Senate are critical of the health insurance provision, and encouraged the House instead to pass a bill approved by the Senate in December that will extend the medical malpractice subsidy through the end of 2008.

The Senate adjourned Monday without acting on the bill sent over by the House.

In the House, Democrats thwarted a move by Republicans to bring the Senate bill to the floor. In addition to extending the medical malpractice subsidy, known as the MCare abatement, that bill would direct $50 million to help hospitals computerize records and institute infection-control practices.

More than 35,000 doctors and other medical professionals originally won the malpractice-insurance subsidy in 2003 when premiums surged.

To pay for it, the Legislature raised cigarette taxes by 25 cents per pack and siphoned money from a separate insurance fund fed by surcharges on traffic tickets.

The subsidy has saved the average primary-care doctor $1,500 a year, while high-risk specialists, including orthopedic surgeons, neurosurgeons and obstetricians, have saved an average of $15,000 a year.