What drug is used as post-exposure prophylaxis for anthrax?

The appropriate drug for post-exposure prophylaxis for anthrax is doxycycline. It is a tetracycline antibiotic that is effective against Bacillus anthracis, the bacterium responsible for anthrax. Doxycycline is often preferred because it has good bioavailability, can be taken orally, and is effective in treating inhalational anthrax, which is the most serious form of the disease that can occur after exposure.

It's important to note that other antibiotics, including ciprofloxacin and penicillin, are also effective against anthrax; however, doxycycline is recommended specifically for post-exposure prophylaxis. The Centers for Disease Control and Prevention (CDC) acknowledges both doxycycline and ciprofloxacin as primary agents for this purpose but emphasizes the broader use of doxycycline due to its additional benefits such as better tolerance and lower risk of resistance. Azithromycin, while it has some antibacterial properties, is not a first-line choice for anthrax prophylaxis.