The nurse is caring for an immunosuppressed pediatric client who reports soreness in his mouth and refuses to eat. Inspection of his mouth reveals a white, milky plaque that do not come off with rubbing. The nurse should anticipate which drug to be administered to this client?

A. Amoxicillin (Amoxil): Amoxicillin is an antibiotic used to treat bacterial infections, but it would not be effective for the condition described. The white, milky plaque in the mouth that does not come off with rubbing is indicative of oral candidiasis (thrush), which is a fungal infection, not a bacterial one. Amoxicillin is not used to treat fungal infections, so it would not address the root cause of the client’s symptoms. B. Acyclovir (Zovirax): Acyclovir is an antiviral medication used to treat infections caused by the herpes simplex virus, such as cold sores or genital herpes. While immunosuppressed clients are at increased risk for viral infections, the clinical presentation described here (white, milky plaque in the mouth) is characteristic of a fungal infection (oral thrush), not a viral one. Acyclovir would not be appropriate for treating fungal infections like candidiasis. C. Metronidazole (Flagyl): Metronidazole is an antibiotic and antiprotozoal drug primarily used to treat infections caused by anaerobic bacteria and certain protozoa (such as Giardia). It is not effective against fungal infections like oral candidiasis. Therefore, metronidazole would not be the appropriate treatment for the client’s oral symptoms. D. Nystatin (Mycostatin): Nystatin is an antifungal medication commonly used to treat oral candidiasis (thrush), which is exactly what the client’s symptoms suggest. The white, milky plaque on the mouth that cannot be wiped off is a hallmark of fungal infection caused by Candida species. Nystatin works by binding to fungal cell membranes and disrupting their integrity, making it the most appropriate treatment in this case. It is typically administered as an oral suspension that the client swishes in the mouth before swallowing or holds in the mouth for as long as possible to ensure the drug is in contact with the infected areas.