For treatment of anthrax disease, IV ciprofloxacin or other fluoroquinolones with CNS penetration are recommended over doxycycline as the primary therapy.

• A. IV Ciprofloxacin or Other Fluoroquinolones With CNS Penetration
• B. Doxycycline
• C. Amoxicillin
• D. Azithromycin

Answer: (A)

When treating anthrax, you want an antibiotic that can rapidly kill Bacillus anthracis and reach the central nervous system if the infection disseminates or involves meningitis. Fluoroquinolones like ciprofloxacin are bactericidal against B. anthracis and achieve reliable CNS concentrations, making them the strongest first-line choice for primary therapy in severe or systemic disease. Doxycycline is active but generally bacteriostatic and doesn’t provide the same rapid kill and CNS penetration as a CNS-penetrant fluoroquinolone, so it’s not the preferred primary option. Amoxicillin and azithromycin have less robust activity or pharmacokinetic coverage for anthrax, so they aren’t chosen as the primary therapy.