Final answer:
For an anorectal viral infection, a nurse should anticipate administering Acyclovir (Zovirax), which is an antiviral medication, not antibiotics like Doxycycline, Penicillin, or Metronidazole.
Step-by-step explanation:
If a patient is admitted with symptoms of an anorectal infection and cultures indicate a viral infection, the nurse should anticipate the administration of an antiviral medication. Among the drugs listed, Acyclovir (Zovirax) is an antiviral medication indicated for the treatment of viral infections, such as different types of herpes infections, which can include anorectal herpes.
Doxycycline (Vibramycin) is a tetracycline antibiotic used for bacterial infections, Penicillin is a beta-lactam antibiotic for bacterial infections, and Metronidazole (Flagyl) is also used to treat certain bacterial and parasitic infections. These are not suitable for viral infections; therefore, the correct drug to anticipate would be Acyclovir (Zovirax), answer A.