WASHINGTON (AP) -- Critics are calling for major new curbs on who can get a prescription for the acne drug Accutane, after voluntary restrictions failed to reduce the number of pregnancies among women using the birth defect-causing medicine.

The Food and Drug Administration is asking its scientific advisers what additional safeguards are needed to battle the birth-defect problem that Accutane has posed since it first hit the market in 1982.

One of those advisers charged the FDA missed a crucial opportunity for better safeguards three years ago -- by ignoring this same panel's recommendation that Accutane be sold only to female patients enrolled in a national registry, with mandatory pregnancy testing.

Instead, the FDA opted for essentially voluntary restrictions, partly because of legal questions about patient privacy.

Failure of those restrictions means it's now time to make Accutane one of the nation's most restricted drugs by replacing routine sales with a special controlled-access program, said FDA panelist Dr. Curt Furberg of Wake Forest University.

"The history of Accutane is an example of inadequate and ineffective risk management by the FDA and the manufacturer of Accutane, to the detriment of thousands of women," wrote Furberg, who missed Thursday's meeting but sent a letter with his views to fellow advisers.

Acknowledging more protection is needed, Accutane maker Hoffman-La Roche Inc. and three generic manufacturers are proposing a somewhat stricter system that would allow the drug's use and distribution only by patients, doctors and pharmacists who are tracked on a national registry.

Going further, as Furberg and some other critics suggest, might encourage women to seek Accutane on the Internet without any medical supervision, said Roche spokeswoman Carolyn Glynn. "We're trying to find a balance."

The full advisory panel will issue recommendations Friday.

If a woman becomes pregnant while taking Accutane, her baby can suffer severe brain and heart defects, mental retardation and other abnormalities, even if the mother took only a small dose for a short period.

The FDA has well over 2,000 reports of women on Accutane becoming pregnant since 1982, when the drug began selling. The vast majority opted for abortion. While some healthy babies were born, the FDA counts more than 160 babies born with Accutane-caused birth defects in that time.

Warning after warning to doctors and patients didn't help, so in 2001 the FDA settled on some broad restrictions: Doctors were supposed to ensure female patients had two negative pregnancy tests and agreed to use two forms of contraception before prescribing Accutane. Pharmacists were supposed to fill only prescriptions bearing a special sticker certifying doctors had done that. Women could get a month's supply at a time, with refills dependent on another negative pregnancy test.

In the first year of those restrictions -- spring 2002 to spring 2003 -- the FDA counted 120 pregnancies among Accutane users, just seven fewer than in the year before the new program.

There's no way to know if the FDA counted all the pregnancies, since reporting them is voluntary; one critic suggests almost five times as many may have occurred.

Nor could the FDA track all the pregnancies. Of 29 known live births, the FDA attributed Accutane-caused birth defects to four.

At the same time, total prescriptions for Accutane and its generic version, called isotretinoin, dropped 23 percent, from 1.5 million to 1.16 million.

Part of the problem is overuse of Accutane, critics say. It is intended for people with very severe acne, the kind that causes large cysts and leaves deep scars, yet often is prescribed for mild acne.

Copyright 2004 The Associated Press. All rights reserved.