A drug company has decided to put a stronger warning on a new acne medication after three women who took the drug delivered deformed infants.

The drug, called Accutane, was given priority clearance by the Food and Drug Administration in May, 1982, despite evidence that it caused birth defects in laboratory animals. The agency approved Accutane so fast that it took the drug's surprised manufacturer nearly four months to get it on the market.

The FDA called the drug a "significant advance" in the treatment of cystic acne, a particularly severe form of the skin disorder, and said its potential benefits to an estimated 360,000 victims outweighed its side effects.

In addition to birth defects, which showed up in animal studies, tests on 170 human patients showed that the drug can cause chemical abnormalities in the liver, skin infections, inflammation of eye membranes and increased sensitivity to the sun.

Its manufacturer, Hoffman-La Roche Inc., put Accutane on the market last September, with a warning that it should not be taken by pregnant women or people with liver ailments. The company also suggested that women of child-bearing age use an effective contraceptive while taking Accutane and for at least a month after discontinuing its use.

"Unfortunately, despite our efforts, there are three known cases of women who have carried to full term and borne infants with severe central nervous system defects," a Hoffman-La Roche spokesman, Carolyn Glynn, said yesterday.

Glynn said Hoffman-La Roche learned of the cases in late June and was still investigating them. "We don't know exactly what took place," she said. "It's too early to know that."

An estimated 200,000 patients have used Accutane in the United States, the first nation to approve its use. The drug has since been given the green light in Canada, and it went on sale in Britain earlier this month.

Glynn said the drug is a "major product" for Hoffman-La Roche, and the company has no plans to take it off the market. Instead, the firm has elected to strengthen previous warnings.

Hoffman-La Roche notified the FDA of the birth defects several weeks ago, as required by federal law. Last week it mailed more than 500,000 letters to physicians and pharmacists, reminding them that the drug should not be used during a pregnancy.

The firm says it will issue special warning stickers to pharmacists and will revise warnings on package inserts.