The American Medical Association's failure to curb the Federal Trade Commission's power, despite almost $2.5 million in campaign contributions, may have cost the AMA future support from many of its philosophic allies in Congress.

Anti-AMA forces in the Senate were mobilized by middle-of-the-road Republicans instead of the liberal Democrats who had led the fight against organized medicine in the past. Furthermore, some of the Senate's most conservative members joined in on the side of the FTC to vote against the AMA.

"I think they have suffered a significant blow. There's no question that it's one that's going to be really hard to recover from," said Willis D. Goldbeck of the Washington Business Group on Health.

"It is a repudiation of the public equating whatever a physician says or does with quality care," added Goldbeck, whose organization represents big business on federal health-care issues. Two hundred of the Fortune 500 companies belong to his group.

The AMA, nonetheless, insisted it really had won because, as a result of their lobbyists' actions Sunday, there is nothing in the FTC money bill that specifically gives it authority to regulate professionals such as doctors and lawyers.

The AMA started its campaign against the FTC after the commission began looking in the late 1970s for anticompetitive aspects of organized medicine, including restrictions on advertising and bans on doctors who work in prepaid practices charging less than the going fees.

The FTC also began looking into activities of state medical associations, including charges that rural health clinics in Alabama were forced to close because they were run by nurse-practitioners, not doctors.

"The American Medical Association now looks forward to a victory in the next Congress, when the House and Senate can act to maintain doctors' rights to carry out patient advocacy," said AMA Executive Vice President James H. Sammons.

Another AMA official asserted, "We were successful." He then added, "We're exactly where we were two years ago. So we start again next year."

Standing still, however, was accomplished at great cost to the AMA. According to Ralph Nader's Congress Watch, the AMA spent $1.98 million in the past two elections on campaign contributions to members of the House and $450,750 since 1978 on campaign contributions to senators. Passage of a bill to curb the FTC was organized medicine's major legislative effort during the past 1 1/2 years.

It appeared last month that the contributions and lobbying had paid off when the House included curbs on FTC powers over the professions in the commission's authorization bill. But that bill died, and the continuing resolution contained no such legislation.

Furthermore, Sen. Warren Rudman (R-N.H.), a conservative first-termer who previously has taken little interest in health-care legislation, led the Senate fight for a compromise amendment that would bar the FTC only from licensing aspects of the professions already covered by the states.

It was passed with the votes of Senate conservatives such as Strom Thurmond (R-S.C.), Harry Byrd (Ind-Va.), Gordon J. Humphrey (R-N.H.) and Dan Quayle (R-Ind.) -- people the AMA could count on in the past to support it against the onslaught of liberals such as Sen. Edward M. Kennedy (D-Mass.).

Although FTC Chairman James C. Miller III considered the Rudman amendment a victory because it preserved most of the commission's authority to police trade practices of the professions, health-care groups such as the nurse-midwives -- who complain doctors are blocking their right to practice through licensing powers -- opposed it.

According to AMA and FTC sources, lobbyists from organized medicine prevailed on House members of the House-Senate conference on the continuing resolution to delete the Rudman amendment. The AMA wanted the amendment out to make sure that nothing in the law specifically mentioned FTC authority over the professions, sources said.