Some drugs make you high, some drugs make you feel low.Quaaludes make you sleepy.

Originally developed and marketed in 1965 as a sleeping potion and sedative, the methaqualones - including Quaalude, Sopor and Parest - became popular "recreational" drugs in the late 1960s and early 1970s. They had two attractions.

The first was the drugs' purported aphrodisiac qualities. Users reported that the white pills prolonged and heightened the enjoyment of sex.

The second was the drug's sedative effect, which many rock concert aficionados found to be the perfect complement to the thunderous volume of driving rock.

"They make yu feel like silly putty," said one woman of Quaalude tablets. "Your joints and limbs get all loose. It's just silly."

And what about the sexual properties of the drug?

"I fell asleep," she replied.

Another woman said she "had a friend who used to do so many she'd fall down and bang her knees all up. I don't know why people take it. But if you're hyper, it smooths you out. You can get stuck in time. Everything comes to a halt. It's a mellow drug." As for sex, she said, "I lost interest in it.

Whatever the attraction, it was a great one. In 1973 Parke, Davis & Co. reported the disappearance of 600,000 tablets of its brand of the drug and asked the government for security help.

After hearings by the Senate's Subcommittee on Juvenile Delinquency - which included repeated testimony from former users about the drugs' psychologically addictive properties - the Bureau of Narcotics and Dangerous Drugs, now the Drug Enforcement Administration, placed the various brands of methaqualone on Schedule II of restricted drugs.

Schedule I drugs, including heroin, are those substances considered not medically useful that have a high potential for abuse.

Schedule II drugs, including Quaaludes and morphine, are drugs with legitimate medical purposes but also with a high potential for abuse.

In addition to being potentially psychologically addictive, Quaaludes can be fatal when used in combination with alcohol. The user can slip from the drug-induced stupor into a coma from which he will never emerge.

A Schedule II drug may be prescribed only by a physician with a DEA registration number, which virtually all physicians have. Pharmacists are required to keep detailed records of all sales of such drugs - records including the name and address of the prescribing physician, the name and address of the patient and the quantity of drug dispensed.

As one former researcher of the National Institute on DrugAbuse said, "Quaaludes are tough to get now," and their use has fallen off.

In 1973, an 18-month federal study concluded that the drug was involved in 145 suicides and 906 overdose cases, in addition to numerous suicide attempts and personal injuries.

In the three-month period ending in December 1977, the Drug Abuse Warning Network reported 658 "mentions" of methaqualones in emergency rooms across the country. A person's coming into an emergency room for treatment, saying he has taken a particular drug, constitutes a "mention."

In that period, methaqualones accounted for 1.5 percent of the 44,241 "mentions" nationwide - compared to Librium, which accounted for 1.7 percent of the mentions, and Valium, which made up 11 percent.