Maybe Elvis would be as "Alive!" as the tabloids say he is if legislation now pending before Congress had been passed 20 years ago.

To curb addictions to prescribed drugs and black market sales of those drugs, Congress is considering policing prescription drugs and saving some money in the Medicare budget at the same time.Rep. Fortney "Pete" Stark, D-Calif., has proposed requiring all doctors to write prescriptions in triplicate - one copy for the patient, one for the doctor and one for the state health agency. The theory is that doctors will be less inclined to over-prescribe addictive drugs if they know the state is counting.

And Stark thinks he can save $1 billion a year in Medicaid payments now going to unnecessary prescriptions.

Drug companies are terrified of the proposal, but they have been strangely silent on Capitol Hill. Instead, they have left the lobbying to patient-rights groups that bark warnings about putting Big Brother in the doctor's office.

For all their good intentions, the patient-rights advocates are not as small and powerless as they appear. Many of them are heavily backed with contributions from the big drug companies.

For example, in 1988, the Upjohn Co. contributed $127,951 to the Phobia Society, more than the group received that year from its entire membership. The group now goes by a new name - the Anxiety Disorders Association of America - and is among those fighting Stark's legislation.

We asked Upjohn how much the pharmaceutical company gave to patient-rights groups last year. A spokesman for the company couldn't find the records, but he noted that Upjohn feared Stark's bill could keep patients from getting drugs they need.

Police and federal investigators think the triplicate prescription idea will put a chill on unnecessary and illegal prescriptions, not on legitimate ones.

The illegal sale of prescribed drugs is big business - $25 billion a year on the black market, according to the Drug Enforcement Administration. Prescription drugs kill or injure three times as many people as heroin each year. One-third of the overdose cases brought into emergency rooms involve legal drugs.

The problem rarely gets attention unless a celebrity like Elvis Presley overdoses or a public figure like Kitty Dukakis admits an addiction.

Three doctors in Los Angeles were recently accused by the Medical Board of California of over-prescribing addictive drugs to actress Elizabeth Taylor. According to the complaint, the doctors gave Taylor more than 1,000 prescriptions for 28 controlled substances.

On the street, the market for prescription drugs is so busy that it takes a full unit of the DEA to keep track of it.

One veteran federal investigator told us about a bust of "doctor shoppers" in Georgia who rounded up elderly cancer patients and drove them around to different doctors for prescriptions of Dilaudid, also known as "drug store heroin." The pills sell at a pharmacy for about $1 each, but on the street they are worth $50 each.

What will state agencies learn by getting copies of all prescriptions for addictive drugs? A spot survey by federal investigators offers one example. They recently discovered that one doctor in New Mexico prescribed about one-fourth of all the tranquilizers paid for by Medicaid in that state.