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Bioterrorism > Agents > Anthrax > Questions & = Answers=20 >

Anthrax Q & A: Preventive Therapy

In the event that persons are exposed to potentially = aerosolized=20 Bacillus anthracis spores, what will CDC recommend to prevent=20 inhalation anthrax?
CDC will recommend 60 days of selected = oral=20 antibiotics in conjunction with a 3-dose regimen (0, 2 weeks, 4 weeks) = of=20 anthrax vaccine (BioThraxT, formerly known as AVA) as an emergency = public health=20 intervention. Two major U.S. national advisory bodies have considered = strategies=20 for post-exposure prophylaxis for prevention of inhalation anthrax among = individuals exposed to potentially aerosolized B. anthracis = spores.=20 Both groups, the Advisory Committee on Immunization Practices (ACIP) and = the=20 John Hopkins Working Group on Civilian Biodefense, concluded that based = on=20 available data, the best means for prevention of inhalation anthrax is = prolonged=20 antibiotic therapy in conjunction with anthrax vaccination. In addition, = a=20 recent Institute of Medicine Report on anthrax vaccine safety and = efficacy also=20 concluded that based on limited animal studies, anthrax vaccine = administered in=20 combination with antibiotics following exposure to B. anthracis = spores=20 may help to prevent the development of inhalation anthrax.=20 BioThraxT is not licensed for post-exposure prophylaxis = for=20 prevention of inhalation anthrax, or for use in a 3-dose regimen; = therefore,=20 this program would be conducted under an Investigational New Drug (IND)=20 application.

Why does CDC recommend 60 days of = antibiotics?
Anthrax=20 spores grow like plant seeds. If you plant seeds and give them sun and = water,=20 they will grow into plants. If you give anthrax spores the right = environment,=20 such as the human body, they can grow into the harmful form of the = bacteria that=20 can cause anthrax disease. It takes anthrax spores an average of 7 days = to grow=20 into the harmful form of the bacteria, but it can take longer. For this = reason,=20 CDC recommends preventive antibiotics for the full 60 days.

Which antibiotics does CDC recommend for prevention of = inhalation=20 anthrax?
In selecting an antibiotic, we will be guided by = the=20 organism's culture and sensitivity results, history of allergic = reactions, age=20 and health status factors and antibiotic availability. When no = information is=20 available about the antimicrobial susceptibility of the implicated = strain of=20 B. anthracis, initial therapy with ciprofloxacin or doxycycline = is=20 recommended for adults and children, or levofloxacin for adults.

What drugs are FDA-approved for postexposure prophylaxis = (PEP)?=20
Ciprofloxacin and doxycycline are FDA-approved for PEP in = adults=20 and children, and levofloxacin is FDA-approved for PEP in adults ages 18 = and=20 older.

Are there special instructions for taking ciprofloxacin or=20 doxycycline?
As with all antibiotics, take the medication = according=20 to the schedule you were instructed, and even if you begin to feel = better,=20 continue taking it for the full number of days.

What is cipro (ciprofloxacin)?
Ciprofloxacin, or = cipro=20 as it is commonly known, is a broad-spectrum, synthetic antimicrobial = agent=20 active against several microorganisms. The use of ciprofloxacin is = warranted=20 only under the strict supervision of a physician.

Does ciprofloxacin have an expiration date?
Yes. = Antibiotics, just like all medicines, have expiration dates. If you = received=20 your ciprofloxacin through a pharmacist, the expiration date should be = listed on=20 the bottle. If you can't find it or have questions about the expiration = date,=20 contact your pharmacist directly.

What side effects could I get from taking cipro? =
Common=20 side effects of Cipro include an upset stomach, vomiting, diarrhea, = fatigue,=20 dizziness, or headache. If you have problems with any of these symptoms, = tell=20 your doctor. Less common side effects include pain in arms or legs, = changes in=20 vision, restlessness, ringing in the ears, or mental changes. If any of = these=20 symptoms occur, call your doctor right away.

Can other fluoroquinolones be used instead of ciprofloxacin = for=20 postexposure prophylaxis (PEP)/treatment?
Other = fluoroquinolones,=20 such as ofloxacin and levofloxacin, are not specifically recommended as=20 alternatives to ciprofloxacin because of a lack of sufficient data on = their=20 efficacy. However, if first-line drugs were not available, these other=20 fluoroquinolones may be effective.

Besides anthrax, what else is ciprofloxacin prescribed for? = Has there=20 been resistance to ciprofloxacin when used in other instances = (historically)?=20
Ciprofloxacin is a broad-spectrum, highly effective = antibiotic that=20 has been part of the "international traveler's" kit at CDC for at least = a year.=20 It can be used against most bacterial infections. However, ciprofloxacin = is=20 frequently overused for many diseases that can be treated with less = powerful,=20 narrower-spectrum drugs. Right now, most bacteria are susceptible to=20 ciprofloxacin, which is why we want to be cautious about its use. = Overuse of=20 ciprofloxacin could lead to the development of resistance.

Is there a generic form of ciprofloxacin?
No, = there is=20 currently no generic form of ciprofloxacin in the United States.=20

What side effects could I get from taking doxycycline?=20
Common side effects of doxycycline include an upset = stomach,=20 vomiting, or diarrhea. If you have problems with any of these symptoms, = tell=20 your doctor. Less common side effects include dark urine, yellowing of = the eyes=20 or skin, sore throat, fever, unusual bleeding or bruising, fatigue, = white=20 patches in the mouth. If any of these symptoms occur, call your doctor = right=20 away.

What side effects could I get from taking amoxicillin?=20
Common side effects of amoxicillin include an upset = stomach,=20 vomiting, and diarrhea. If you have problems with any of these symptoms, = tell=20 your doctor.

What side effects are serious enough that I should go to a = doctor?=20
Any side effect that forces you not to take your medicine = is=20 serious enough that you should consult or see your doctor.

Serious side effects of ciprofloxacin include seizures, mental = confusion,=20 rash that does not go away, or excessive diarrhea.

If you have any of these effects, call your doctor.

Serious side effects of doxycycline include jaundice (yellow eyes or = skin),=20 rash that does not go away, or excessive diarrhea. If you have any of = these=20 effects, call your doctor.

Any reaction that causes a rapid swelling of the lips and face, = shortness of=20 breath, or hives is a medical emergency. You should call 911. These = types of=20 reactions are extremely rare.

Ciprofloxacin and doxycycline look different and come in = different=20 doses. Is one better than the other?
Ciprofloxacin 500 mg = and=20 doxycycline 100 mg both have the same killing power in your bloodstream = and are=20 equally effective against anthrax bacteria. Both have similar side = effects.=20 Doxycycline is available in both tablet and capsule form. Both will give = you the=20 same amount of medicine in your bloodstream to kill the bacteria.

What if the antibiotics I take gives me headaches? Is there = anything=20 I can do to help this?
If you don't have a history of = headaches,=20 then your headache may be related to the medicine. Changing the time of = day that=20 you take the ciprofloxacin or eating after you take the medicine may = help. Pain=20 relievers such as acetaminophen may help your headache. If your headache = does=20 not go away, you should consult your doctor.

What if the antibiotics I take makes me feel sick to my = stomach? Is=20 there anything I can do to help this?
Taking your = antibiotic with=20 food may help reduce this sick feeling. Ciprofloxacin and doxycycline = should not=20 be taken within 2 hours of taking antacids. Ciprofloxacin and = doxycycline should=20 not be taken with dairy or calcium-fortified products (such as ice cream = or=20 calcium-fortified orange juice).

What if the antibiotics I take give me diarrhea? Is there = anything I=20 can do to help this?
Antibiotics may disrupt bacteria in = the=20 gastrointestinal tract, causing diarrhea. Food may help relieve the = diarrhea. If=20 the diarrhea does not go away, your doctor may recommend another = antibiotic. If=20 you develop severe, long-lasting diarrhea, you may have a serious = condition and=20 should consult your doctor.

If taking one of the recommended antibiotics makes me feel = terrible,=20 can I switch to another of these antibiotics?
If you have = tried=20 taking the medicine with food or changing the time of your dose but = still feel=20 terrible, you should ask your doctor about switching antibiotics.

What if I get a yeast infection while taking antibiotics? Is = there=20 anything I can take for this?
Occasionally, women develop = yeast=20 infections while taking amoxicillin. You may treat the infection with=20 over-the-counter medicines such as clotrimazole. If the symptoms do not = go away,=20 you should consult your doctor.

What if the antibiotics I am taking make me feel itchy all = over. Is=20 there anything I can do to help this?
Rashes that appear = suddenly=20 or do not go away after a few days may be signs of an allergic reaction. = You=20 should see your doctor immediately.

What if the antibiotics give me an allergic reaction and I = stop=20 taking them? What should I do?
If the allergic reaction was = severe=20 or rapid, you should notify your doctor before taking another = antibiotic. Your=20 doctor will prescribe a different antibiotic that will kill the bacteria = without=20 causing an allergic reaction. Remember: you should complete the entire = 60 days=20 of treatment even if you change antibiotics.

Why can't I take a shot, wear a patch, or take one large dose = of the=20 medicine instead of taking it for 60 days?
Spores can stay = in your=20 body for some time before they start growing and causing you to become = ill. When=20 the spores are not growing, antibiotics are not effective. Only after = the spores=20 start to grow can the antibiotics work. Therefore, you need a constant = level of=20 antibiotic in your body for 60 days to make sure that when the spores = start to=20 grow, the antibiotic is there to kill them.

I think I may feel much better if I take only one pill of=20 ciprofloxacin, doxycycline, or amoxicillin each day. Is that okay?=20
No. The drug must be taken twice a day to kill the = bacteria. If=20 your body contains anthrax bacteria and you do not take the full dose, = the=20 bacteria may start to grow again and become harder to kill.

Can I drink alcohol if I am taking antibiotics? =
Social=20 drinking of alcohol (fewer than 2 drinks a day) should not cause any = side=20 effects unless you already have a liver problem. However, drinking too = much=20 alcohol can cause the medicine to leave your body faster, which will = decrease=20 the effectiveness of the medicine. If you drink more than two drinks a = day, you=20 should tell your doctor so that different medicines can be prescribed. =

If I was exposed to Bacillus anthracis and was = prescribed=20 antibiotics, but took the medicine only for a couple weeks, wouldn't = that weaken=20 any anthrax that's in my body?
Inhaled anthrax spores = become lodged=20 in the body and may activate after initial exposure. Antibiotics have = little or=20 no effect when the spores are inactive. To be effective in preventing = inhalation=20 anthrax, the antibiotics must be in your system when the spores = activate. It is=20 necessary to take the medicine for at least 60 days to ensure the best=20 protection against inhalation anthrax.

If an anthrax event occurs, should people buy and store = antibiotics?=20
There is no need to buy or store antibiotics, and indeed, = it can be=20 detrimental to both the individual and to the community. First, only = people who=20 are exposed to anthrax should take antibiotics, and health authorities = must make=20 that determination. Second, individuals may not stockpile or store the = correct=20 antibiotics. Third, under emergency plans, the federal government can = ship=20 appropriate antibiotics from its stockpile to wherever they are needed. =

Will antibiotics protect me from a bioterrorist event? Should = I=20 stockpile them?
CDC does not recommend using antibiotics = unless a=20 specific disease has been identified. There are several different agents = that=20 could be used for bioterrorism, such as bacteria, viruses, and toxins. = Not a=20 single antibiotic (or vaccine) works for all of these agents. = Antibiotics only=20 kill bacteria, not viruses or other agents that could also be used in a=20 bioterrorist event. Antibiotics are not harmless drugs. They can cause = serious=20 side effects and drug interactions. National and state public health = officials=20 have large supplies of needed drugs and vaccines if a bioterrorism event = should=20 occur. These supplies can be sent anywhere in the United States within = 12 hours.=20

When is a 60-day prescription of prophylactic antibiotics not = needed?=20
People who are determined not to be at risk for inhalation = anthrax=20 do not need to take the 60-day course of prophylactic antibiotics. = Prophylactic=20 antibiotics are not indicated for the prevention of cutaneous anthrax, = for=20 hospital personnel caring for patients with anthrax, or for persons who=20 routinely open or handle mail if there has not been a credible threat. =

Page last modified March 25, 2005

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Anthrax Q & A: Preventive Therapy

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