Three health groups sued Health and Human Services Secretary Richard s. Schweiker yesterday, demanding that HHS require drug companies to include pamphlets telling patients the dangers of several prescription drugs when those drugs are sold.

Obeying President Reagan's executive order to freeze new regulations pending reevaluation, HHS' Food and Drug Administration has told drug firms they need not meet previously established May 25 or July 1 deadlines to provide "patient package inserts," pamphlets warning of the possible dangers of five drugs used by millions of patients. Included are pain-killing Darvon, the ulcer drug cimetidine (Tagamet) and cholesterol-lowering Atromid-S. More patient inserts or "PPIs" would have been required soon for transquilizers like Valium and other products.

The suit -- by the Public Citizen Health Research Group, National Women's Health Network and National Council of Senior Citizens -- is one of the first tests of activists' promises to sue the Reagan administration when it tries to blunt or junk regulations intended to protect to public.

Critics of drug over-use and abuse have been urging compulsory distribution of such warning pamphlets for years. They have succeeded in getting them placed in all prescriptions for oral contraceptives, estrogens and some other hormonal drugs, IUD contraceptives and some inhalants.

But an FDA action last September would have starting putting PPIs in more than a sixth of all prescriptions. Nearly 25 million prescriptions were filled for Valium alone in 1979 and 9.7 million for Tagamet.

The proposed PPIs would have warned patients they could become dependent on Valium. They would have said prolonged use of Atromid-S may increase the risk of gallbladder problems and cancer.

Doctors and other health professionals "often do not give out vital information" like this, Dr. Sidney Wolfe, Health Research Group director, wrote to Schweiker. The suit said FDA is required by law to correct "false or misleading" misbranding and has often ruled that not to give patients full information is misbranding.

Wayne Pines, an FDA associate commissioner, said the FDA stay of the PPI regulations establishes procedures to reexamine the need for them. He said Dr. Arthur Hull Hayes of Pennsylvania State University will begin a review after he reports as new FDA commissioner next week.