Healthcare companies are spending millions of dollars and marshaling armies of lobbyists to influence a landmark debate in the U.S. Congress that could dramatically change the way they do business.

Drugmakers, doctors, insurers and hospitals have opened their wallets, spending more than $1 million a day to buy a voice in the escalating political battle over what could be the broadest revamp of healthcare laws in decades.

I hate to use the word free-for-all, but this bill is in play and everyone wants a piece of it, said Bill Buzenberg, executive director of the Center for Public Integrity, a nonprofit investigative group.

Money provides access and access is the name of the game -- it gets you at the table to make suggestions and try to eliminate things you don't like, he said. That's going on now in every congressional office.

The healthcare debate has dominated the U.S. Congress for weeks, with President Barack Obama pushing lawmakers to come up with legislation that will rein in costs, improve care and expand coverage to most of the 46 million uninsured Americans.

As the debate has unfolded, key lawmakers have seen a surge in campaign donations, and hundreds of lobbyists have jammed Capitol hallways and lined the reception room outside the Senate chamber to talk to lawmakers.

This is prime-time for funneling money to the most useful targets, said Sheila Krumholz, executive director of the Center for Responsive Politics, which tracks money in politics.

There is a frenzy going on to get in your two cents worth before the legislation reaches the next stage, she said.

A center report found health companies and groups topped all spending on federal lobbying in the second quarter of the year, forking over a total of $133 million in April, May and June to push their agenda with Congress.

Drugmakers led the way. Senate filings show the Pharmaceutical Research and Manufacturers of America, a trade group that traditionally leads the industry in spending to lobby Congress, poured $6.1 million into the effort in April, May and June.

SPENDING BINGE

The doctors' group the American Medical Association spent $3.8 million, and individual drug and insurance companies also poured money into the debate.

Several upped their spending in the second quarter of the year, according to the reports. Big drugmaker Pfizer Inc (PFE.N) climbed to $5.6 million from $5.3 million in the first quarter; Eli Lilly and Co (LLY.N) jumped to $3.6 million from $3.4 million; Amgen Inc (AMGN.O) increased to $3.4 million from $2.7 million; and GlaxoSmithKline Plc (GSK.L) went to $2.3 million from $1.8 million, the reports showed.

Insurance giant Blue Cross/Blue Shield spent $2.8 million on lobbying in the second quarter; MetLife Inc (MET.N) spent $1.7 million; and Allstate Corp (ALL.N) spent $1.5 million.

The expenditures are designed to protect their interests and help determine how the changes on Capitol Hill might affect their financial bottom line.

Many companies and trade groups in the health sector oppose an option in the House of Representatives' bill for a government-run insurance plan to compete with insurers.

A bipartisan group of Senate Finance Committee members negotiating that panel's bill say their plan is unlikely to include a public insurance plan, which has angered some supporters of the option.

This is not really primarily a healthcare debate. It is a debate about the healthcare industry and the drug companies spending a huge sum of money to try to get their way, Senator Bernie Sanders, an independent and a strong supporter of a public option, told reporters.

The proposals in Congress are far-reaching enough that a diverse array of industry groups unrelated to healthcare have also lobbied on the issue, from soft drink manufacturers worried about new taxes on sugary drinks to Realtors and funeral home directors worried about the impact on small businesses, the Center for Responsive Politics said.

The industry is also a big campaign contributor to members of Congress. Five of the top 10 contributors to Senate Finance Committee Chairman Max Baucus, a key player in healthcare negotiations, have in recent years been drug or insurance companies, according to reports compiled by the center.

A coalition of conservative House Democrats who represent crucial swing votes in the healthcare debate have also seen their donations skyrocket as they have gained prominence, a Center for Public Integrity report showed.

The political action committee for the so-called Blue Dogs broke fund-raising records this year with help from the health industry as well as the energy and financial service sectors, which are also embroiled in landmark climate change and regulatory legislation.