February 13, 2006 ANDREW BRIDGES WASHINGTON - The tens of thousands of Americans who take Accutane to treat their severe acne may gain additional time to register with a program designed to limit use of the birth defect-causing drug by pregnant women, health officials said Friday.

Doctors and patients, along with wholesalers and pharmacies, are supposed to be registered and activated in the computerized iPledge system by March 1 if they want to sell, prescribe or take the acne drug isotretinoin. Isotretinoin is sold as Accutane and in three generic versions: Amnesteem, Claravis and Sotret.

But glitches in the program, as well as the slow progress in registering patients and others, have led to calls for a delay by the American Academy of Dermatology Association and others. The ongoing problems with implementing the new Medicare prescription drug benefit may be complicating the debut of the registry as well, officials said.

The Food and Drug Administration will decide in the next week whether to extend the deadline, said Dr. Sandra Kweder, deputy director of the regulatory agency's Office of New Drugs.

The registry program is the latest in 20 years of FDA efforts to limit the exposure of fetuses to isotretinoin. If a woman uses the drug during pregnancy, or should become pregnant within a month of taking it, her baby runs a significant risk of brain and heart defects, as well as mental retardation.

The iPledge program is to replace and expand on four smaller registries run by the drug's individual manufacturers. The FDA sought the new program because of the estimated 100 to 140 pregnancies a year still being reported in the United States in women on the drug.

The drug is prescribed to about 100,000 Americans a month. As of Wednesday, just 17,881 patients had registered with the program, according to James Shamp, a director of Covance Inc., which runs iPledge.

Most, or 88 percent, of the nation's 55,000 pharmacies have registered, according to data presented by Shamp. However, just 56 percent of the estimated 36,000 doctors who prescribe isotretinoin were registered as of Wednesday.

Since Accutane sales began in 1982, the FDA has received reports of more than 2,000 pregnancies among users. Most ended in abortion or miscarriage, but the FDA counts more than 160 babies born with drug-caused defects.