Long courses of either ciprofloxacin or doxycycline are indicated for prophylaxis in the event of aerosolized anthrax exposure.
Aerosolized anthrax is a potential agent for bioterrorism. Exposures to sporse can lead to local cutaneous infections and inhalation anthrax. Initial symptoms of inhalation anthrax may be like those seen in upper respiratory tract infections or influenza and progress to systemic toxin mediated symptoms, bacteremia, meningoencephalitis and hemorrhagic pneumonia with high mortality rates.
Prophylaxis is recommended within 48 hours of exposures and for 60 days with either ciprofloxacin or doxycycline regardless of the age of the patient. This is to be done in concert with vaccination. The long course is needed due the incubation period after exposure to spores that may not immediately germinate and to allow for the vaccine to take effect. While doxycycline has been demonstrated not to cause tooth staining in short courses this may be a concern in longer courses in those less than eight years of age. Ciprofloxacin in this longer course raises concern for cartilage toxicity.
Alternative agents are: levofloxacin, clindamycin and penicillin or amoxicillin only if documented to be susceptible.
References:
Bradley JS, Peacock G, Krug SE, Bower WA, Cohn AC, Meaney-Delman D, Pavia AT; AAP Committee on Infectious Diseases and Disaster Preparedness Advisory Council. Pediatric anthrax clinical management. Pediatrics. 2014 May;133(5):e1411-36. PMID: 24777226