Note: These questions and answers discuss medicine to prevent anthrax in pregnant women who have been exposed to anthrax, but who do not have symptoms of anthrax disease. For CDC guidelines for treating anthrax disease, see MMWR, October 26, 2001 / Vol. 50 / No. 42

I'm taking a drug to prevent anthrax, and I just found out that I'm pregnant. What should I do?

It is very important that you keep taking the drug that was given to you. You should also contact your health care provider or the local public health officials right away to let them know that you are pregnant. They will want to talk about which drug would be the best choice for you - both to prevent anthrax and to be safe for you and your unborn baby (fetus).

I'm pregnant. Which drug should I take to prevent anthrax? 

You should take a drug to prevent anthrax only if a public health official agrees that you may have been exposed to anthrax. You and your doctor will want to discuss the risks and benefits of the drugs that can be used to prevent anthrax. Which drug is best for you will depend on how and where you were exposed and on your medical history (including other drugs you may be taking and any drug allergies you may have). There are three main drugs used to prevent anthrax: ciprofloxacin, amoxicillin, and doxycycline. Ciprofloxacin works well to prevent anthrax and is not likely to cause major problems for the fetus. But, not enough studies have been done with pregnant women who have taken ciprofloxacin to say that there is no risk to the fetus. Doctors are more certain that amoxicillin is safe for the fetus, but amoxicillin may not always work against anthrax. Before giving you amoxicillin, your health care provider would want to make sure that the strain of anthrax to which you were exposed can be prevented by amoxicillin. Doxycycline can sometimes cause problems for the teeth and bones of the fetus. Therefore, you should not take doxycycline unless there is a reason why you cannot take either ciprofloxacin or amoxicillin. 

I've heard that doctors usually don't give ciprofloxacin to pregnant women. Why is that? Why are they using it to prevent anthrax?

Ciprofloxacin is not likely to cause major problems for a fetus. But, not enough studies have been done with pregnant women who have taken ciprofloxacin to say that there is no risk to the fetus. Ciprofloxacin is not often used with pregnant women since most infections that pregnant women get can be treated with other drugs that are known to be safer for pregnant women. Still, because anthrax is a life-threatening disease, the benefits of using ciprofloxacin may outweigh any risks to the fetus.

I was started on ciprofloxacin to prevent anthrax. I've heard that amoxicillin may be a safer drug for me to take while I am pregnant. How do I know if I can be switched to amoxicillin?

Doctors often feel more certain about using amoxicillin than ciprofloxacin for women who are pregnant because they know more about the safety of amoxicillin for the mother and the fetus. But sometimes amoxicillin may not work against anthrax. This is because anthrax can become resistant to penicillins, like amoxicillin. Before giving you amoxicillin, your doctor will want to learn more about how and where you were exposed to anthrax and also about your medical history. (For instance, some women cannot take amoxicillin because they are allergic to it.) 

Doxycycline was given to my co-workers who aren't pregnant. Is doxycycline a better medicine against anthrax than ciprofloxacin?

No. There is no information to suggest that doxycycline is better than ciprofloxacin to prevent anthrax. 

I'm having a lot of heartburn while I'm pregnant. Can I take ciprofloxacin at the same time as I take antacids?

No. Antacids should not be taken at the same time as ciprofloxacin because they may keep ciprofloxacin from working well. (Antacids can prevent ciprofloxacin from being absorbed and used by the body.) You should not take antacids in the 6 hours before you take a ciprofloxacin pill or for 2 hours after you take ciprofloxacin. 

I've been trying to get pregnant and have just started taking a drug to prevent anthrax. Can I keep trying to get pregnant while taking this drug?

Whether or not to try to get pregnant while taking a drug to prevent anthrax is your choice. When making this choice, you should discuss the risks and benefits with your family and your health care provider. Some women may want to wait until after taking the full course of antibiotics before getting pregnant. If you decide not to wait, it may be best not to take doxycycline unless there is a certain reason why you cannot take either ciprofloxacin or amoxicillin. 

I just found out I'm pregnant, and I was exposed to anthrax at work. I want to take the best drug for my baby and me, but I don't want my boss to know yet that I'm pregnant. What should I do?

It is very important that you tell your health care provider or local public health officials that you are pregnant. They will not be required to tell your boss. 
 

Date: October 5, 2005
Content source: National Center on Birth Defects and Developmental Disabilities