Following a possible exposure to Bacillus anthracis spores, prophylaxis should be initiated and continued while the exposure is confirmed or excluded. Prophylaxis consists of both chemoprophylaxis and vaccination. Contaminated clothing and surfaces should be decontaminated.


Postexposure Chemoprophylactic Regimens


Drugs of choice for chemoprophylaxis: Oral fluoroquinolones

(1) ciprofloxacin

(1a) adult: 500 mg bid

(1b) pediatric: 20-30 mg per kg per day, half given q12h

(2) levofloxacin

(2a) adult: 500 mg bid

(2b) pediatric: not recommended

(3) ofloxacin

(3a) adult: 400 mg bid

(3b) pediatric: not recommended


If fluoroquinolones are not available or are contraindicated, doxycycline can be given:

(1) adult: 100 mg bid

(2) pediatric: 5 mg per kg body mass per day, half given q12h



(1) Ciprofloxacin or doxycycline can be used due to risk of life-threatening infection

(2) If Bacillus anthracis exposure confirmed and cultures are available, pediatric patients should be switched to amoxicillin if the isolate is penicillin susceptible. Dosage is 40 mg per kg per day (maximum 1500 mg), divided for q8h administration.


Pregnant women:

(1) Ciprofloxacin is drug of choice despite concerns for fetus due to the risk of a life-threatening infection.

(2) Patients should be switched to a penicillin if the isolate is shown to be penicillin susceptible.


Duration of chemoprophylaxis:

(1) If the exposure to anthrax can be excluded, then chemoprophylaxis can be discontinued.

(2) If confirmed, prophylaxis is continued to 4 weeks and is discontinued only after all 3 doses of vaccine have been given.

(3) If vaccine is not available, chemoprophylaxis is given for 8 weeks.


Postexposure Vaccination


An inactivated, cell-free vaccine is administered together with chemoprophylaxis if the exposure is confirmed.


Administration schedule: 3 doses:

(1) as soon as possible after exposure incident

(2) 2 weeks after exposure

(3) 4 weeks after exposure


Safety and efficacy has not been evaluated in children < 18 years of age or adult > 60 years of age.




Clothing and personal effects should be removed and placed in plastic bags. The bags should be labeled with the person's name, date and the contents of the bag.


Individuals should shower with large amounts of soap and water.


Potentially contaminated environmental areas should be decontaminated with a 0.5% sodium hypochlorite solution (one part bleach to 10 parts water).


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