A major overhaul of prescription drug laws, designed to get important medicines in use faster but also remove harmful ones faster, was passed unanimously by a key Senate committee yesterday at the urging of its chief author, Sen. Edward M. Kennedy (D-Mass.).

On a 13-to-0 vote, the Labor and Human Resources Committee adopted a bill developed over four years by Kennedy, with concessions to committee Republicans, instead of a version offered by President Carter.

The Department of Health, Education and Welfare's acting food and drug commissioner, Sherwin Gardner, promptly called the bill a "reform" measure "we can support," however, and one that could lower drug prices by stimulating drug development.

Gardner also urged the House commerce Committee's health subcommittee to consider the issue soon. Actually, no one expects a House vote before next year, though the Senate is expected to act this fall.

If anything like either the Senate or Carter bill passes both houses, and most observers think that could happen, it would be the most far-reaching change in prescription drug regulation since 1938, when the modern food and drug law revisions were passed.

The bill that passed the Senate committee yesterday would establish the first regular federal surveillance of prescription drug use across the country, for example. The results could put strong pressure on doctors who overuse or misuse powerful drugs.

The bill would halt drug companies' gifts of anything worth more than $10 to induce doctors to use their products. Drug firms have given some doctors TV sets and free trips, and have offered free black bags to new medical graduates.

The most recent major change in the drug laws came with the Kefauver amendments of 1962. They were adopted on the heels of the tragedy of the drug thalidomide, the tranquilizer that caused birth defects in thousands of babies throughout the world.

The Kefauver amendments ordered far more elaborate animal and human testing to prove that drugs are both safe and effective.

But the testing and attendant red tape and paperwork and the timidity of some FDA officials who fear approving some new thalidomide have created a "drug lag," a delay of years in approving effective drugs in use in other nations, many FDA critics have charged.

These critics include both drug firm officials and many medical professors. In June, Congress' General Accounting Office agreed with them, after a two-year investigation.

Then-FDA commissioner Dr. Donald Kennedy insisted that any lag was minor, and when it comes to truly life-saving drugs, any differences between the United States and other advanced countries are "relatively small."

Kennedy nonetheless sent Congress the administration bill to speed up both drug approvals and drug withdrawals, and also did much to hasten the paper-handling in his agency.

One of the administration bill's main features was a plan for a "monograph" system of drug approval, one in which a manufacturer would have to publish what amounted to a tome revealing thousands of details about a proposed drug's testing and characteristics.

Kennedy's bill would junk that plan but, Kennedy has said, get at the same basic goals.

Among other features, the bill would also:

Let FDA allow some drugs on the market that might never be approved today because of possible dangers. But their use would be restricted to hospitals or certain medical specialists, instead of letting them be prescribed by any doctor. This procedure would be applied only to so-called "breakthrough" drugs, those which would help in serious diseases where there is no equivalent treatment.

Let FDA remove a drug from the market if it caused an unreasonable risk to any part of the population. Today FDA can totally ban a drug only if it can prove an "imminent hazard" to public health, a condition that has been hard to prove in court.

Let firms export some drugs prohibited in this country, if the Health, Education and Welfare secretary rules that export would, on balance, help rather than harm the foreign patients.

Let a firm start some initial drug testing without FDA approval if the tests are endorsed by a hospital's or university's ethical review board.

Let firms start making some established drugs without duplicating human testing.

Opposition to the bill, or some parts of it, is expected both from the Pharmaceutical Manufacturers Association and some consumerists. the PMA wants even speedier drug approval. Some consumer groups say they fear any speed-up would loose harmful drugs on the public.