Anthrax prophylaxis, treatment during pregnancy. (Ciprofloxacin, Doxycycline, Penicillin).

The decision about which drug to prescribe for anthrax prophylaxis or therapy should always be based on what's best for the mother, according to Gerald Briggs, clinical professor of pharmacy at the University of California, San Francisco.

Severe maternal toxicity can result from anthrax exposure. In this situation, fetal safety becomes a secondary issue, even though prolonged antibiotic courses, in the absence of a vaccine, raise some safety concerns for the fetus, said Mr. Briggs, the pharmacist clinical specialist at Women's Hospital, Long Beach (Calif.) Memorial Medical Center.

Mr. Briggs, coauthor of the textbook "Drugs in Pregnancy and Lactation" (Baltimore: Williams & Wilkins, 1997), made these recommendations on the safety of various agents for anthrax prophylaxis and treatment:

* Ciprofloxacin (Cipro). The benefits of ciprofloxacin "certainly outweigh the risk," Mr. Briggs said. While there has been some concern that ciprofloxacin exposure in utero maybe related to some birth defects, no causal relationship has been established.

There is a theoretical risk of cartilage damage in exposed fetuses and subsequent arthropathies, and there have been reports of cartilage damage in infants given the drug directly.

* Doxycycline. He considers the tetracyclines to be the last choice for pregnant women. Doxycycline is not a human teratogen but can cause discoloration of primary teeth when exposure occurs anytime from the middle of the second trimester to term. While inhibition of fetal bone growth can also occur, this has not been clinically significant, but prolonged exposure has not been studied. Still, although Mr. Briggs considers this class of drugs to be the last choice for use in pregnancy if a woman had no other choice, she should take them.