A Food and Drug Administration rule, whose long history provides a case study of the waxing and waning of Washington's regulatory fever, has now become the center of a fight between the deregulatory forces of the Reagan administration and Ralph Nader-led consumer groups.

The latest of the regulations for so-called "Patient Package Inserts" was placed on hold by the new administration in February; it has since been listed as one of the rules to be reviewed and possibly dismembered. Consumer groups, among them Nader's Public Citizen Inc., have retaliated by taking the FDA to court, claiming the delay amounted to an illegal suspension of the rule.

The groups' challenge was rebuffed by a U.S. District Court judge here July 31; they have filed an appeal.

There are two issues in the debate over the regulations: how much information should patients have about the drugs they take and who should control the distribution of that information?

For years, the FDA has required pharmacists to give the users of three drugs -- birth control pills, estrogens and synthetic forms of the female hormone progesterone -- informational flyers explaining the drugs' desired effects and possible side effects. Then, in the early years of the Carter administration, the agency proposed expanding the program to almost all prescription drugs.

Last year the proposal was scaled down to a three-year pilot program expanding the use of the package inserts to 10 more drugs or drug classes, including the two most widely prescribed drugs in the country -- cimetidine, which is used to treat ulcers, and the tranquilizer Valium. Also included were propoxyphene, a painkiller marketed as Darvon, and the morning-sickness drug Bendectin.

None of the groups opposing the rule, including the American Pharmaceutical Association (APhA) argues against giving patients information about most drugs. The argument instead turns on whether the program should be mandatory and what purpose the inserts are supposed to serve: to inform patients about drugs or to discourage drug use.

The American Medical Association, in fact, was relatively pleased with the 10-drug plan. They liked it because it would test the whole concept and because it allowed doctors to keep patients from seeing inserts if they felt the information would adversely affect the treatment, according to John Ballin, who heads the AMA's drug division.

The APhA's opposition is stronger: it contends a voluntary program would keep patients adequately informed about the drugs they take. "I think the inserts get into too much detail for the patient," said Dorothy Smith of the APhA. "It's not the patient's responsibility to monitor his own therapy."

But Sidney Wolfe, who heads Ralph Nader's Health Research Group, argues, "You cannot rely on any voluntary mechanism for doctors and pharmacists to give out this information." Wolfe said he favors a general reduction in drug use, contending "there is very strong evidence of gross misuse and overuse."

FDA Commissioner Arthur Hull Hayes Jr., who has scheduled a public hearing on the proposed rule Sept. 30, said, "I firmly believe that patient information about the drugs they take is terribly important. It's also important to look at any way this can be done in an effective way, keeping the costs . . . commensurate with what you're doing." Hayes says he expects to make a decision on the 10-drug program by the end of this year.

The APhA has estimated that the program would cost almost $500 million for printing, packaging, labor and returned prescriptions -- an estimate more than eight times larger than the FDA's. Dr. Richard Penna of the APhA further questioned the purpose of the inserts, asking, among other things, if they were simply meant to inform or actually supposed to discourage overuse of medications.

In the cases of all three drugs now requiring the flyers, usage has declined, though experts caution that many factors -- including negative publicity about a drug or studies that left physicians disenchanted with a compound -- may lead to decreased use.

For example, in the first years after inserts were required for the Pill in 1972, use continued to climb. But after reaching a peak of 64 million prescriptions in 1975, usage declined dramatically, falling to 44.6 million -- a drop of 31 percent -- by 1980, according to drug industry figures obtained by Wolfe. But usage of Valium also declined by 45 percent, although the FDA required no insert at that time.

Other studies are contradictory. The Rand Corp. has just completed a $450,000 FDA-sponsored study that reportedly shows that while most patients read and like the inserts, very few people return prescriptions or change the way they use drugs after reading the flyers. The study is set for release this week.