One of the government's major programs for preventing poisoning is being dismantled, a victim of budget cuts and its own successes.

Already, a nationwide computer network designed to give doctors instantaneous access to data on poisonous household substances has died. And in October, the rest of the National Clearinghouse for Poison Control Centers will be reduced to a skeleton staff, who will not be able to analyze the information it collects.

The program, its director says, "is about to go down the tubes."

The poison-control clearinghouse was created 25 years ago by the surgeon general with a twofold mission. It was to collect data on the toxicity of consumer products and to provide information for treating and preventing poisoning, particularly the poisoning of children, to poison-control centers throughout the country.

In addition, it was to collect and analyze information on the poisoning cases reported to the centers. It was then supposed to try to identify problems, such as trends in drug abuse, drugs that could be confused and supposedly child-proof packages that weren't.

But the clearinghouse's first job was eliminated last year, and projected budget cuts will cripple efforts to analyze cases to prevent future poisonings, according to Dr. Mark I. Fow, director of the Food and Drug Administration's Division of Poison Control, who directs the program.

Part of the program's problem is that it may have done its job too well. FDA budget officials said that fatal poisonings of children have dropped between 80 to 90 percent in the past 20 years. In addition, private industry has become more active in supplying information to the more than 500 volunteer poison-control centers that have sprung up around the country.

Fow acknowledges such arguments, but adds, "Acute poisoning remains an important public health problem. On the order of 5 million toxic substance exposures occur each year leading to 250,000 hospital visits and 10,000 to 15,000 acute poisoning deaths," more than half of which involved products approved by the FDA.

For instance, the clearinghouse recently found that camphorated oil, a common liniment for sore muscles, is sometimes mistaken for castor oil because the bottles look alike. Drinking the liniment can cause convulsions, and for children under 2 or adults over 50, it could be fatal, although there have been no deaths reported in recent years.

The clearinghouse was also able to track the overnight popularity of the drug PCP among teen-agers. "When the poison-control centers report two cases of PCP abuse one year and about 500 the next," as occured in the mid-1970s, Fow said, public health officials know attention should be directed toward that drug.

The clearinghouse operation reached its peak in 1972-73, when it had a $750,000 budget, a staff of 25 and big plans for its nationwide computer network.

In the next few years, the demand for information fell as industry stepped up its activites. In fiscal 1980, the computer network, which had been enormously expensive in a 10-city pilot project, was dismantled. Then when fiscal 1981 budget cuts prompted FDA to reduce the clearinghouse staff to 10, it stopped distributing treatment information.

By the current fiscal year, the budget for the clearinghouse was only about $250,000 and it stopped publishing public service pamphlets such as "Dennis the Menace Takes a Poke at Poison," a comic book designed for children, and "Poisonous Plants." The clearinghouse also stopped its monthly bulletin to poison-control centers.

But Fow says what concerns him the most is the staff cuts scheduled for fiscal 1983. With only five persons, he said, the clearinghouse will have to put the poisoning reports it receives "into boxes until additional staff can be hired to analyze them."

As its functions gradually disappear, the fate of the clearinghouse also appears clouded. If the clearinghouse is eliminated, "nothing drastic will happen," said Fow. "People aren't going to start falling over like flies. But I think we'll lose touch with a lot of what's happening to people and the poisoning problem."