A community health nurse must ensure which medication is available for individuals exposed to anthrax?

Ciprofloxacin (Cipro) is the correct choice because it is a fluoroquinolone antibiotic that is effective against anthrax, particularly the inhalational form, which is a significant concern in bioterrorism. It works by inhibiting bacterial DNA replication, making it effective against the Bacillus anthracis bacterium that causes the disease. The CDC recommends ciprofloxacin as a prophylactic treatment for individuals potentially exposed to anthrax, especially in outbreak scenarios.

Other medications listed have different uses. For instance, metronidazole is primarily used to treat infections caused by anaerobic bacteria and certain parasites, and is not indicated for anthrax. Zanamivir is an antiviral medication used to treat influenza, and fluconazole is an antifungal used to treat fungal infections, both of which do not have relevance in the treatment of anthrax. Thus, ensuring the availability of ciprofloxacin is crucial in contexts where exposure to anthrax is a risk.