American Association of Critical-Care Nurses (AACN) Certification Practice Test

Which second-line therapy is mentioned for managing C. difficile infection?

1. Oral vancomycin

2. Intravenous fidaxomicin

3. Intravenous metronidazole

4. Oral metronidazole

The correct answer is: Oral metronidazole

Oral metronidazole is considered a second-line therapy for managing a Clostridioides difficile infection (CDI) particularly in patients who either do not respond to initial treatments or in specific clinical situations. Current guidelines indicate that metronidazole can be effective in treating mild to moderate cases and may be employed when vancomycin, which is usually the first choice for treatment of CDI, is either unavailable or not tolerated. Intravenous metronidazole is not as effective for CDI due to poor gastrointestinal absorption when administered this way, making it less favorable. Oral vancomycin is typically the first-line treatment. Intravenous fidaxomicin is not commonly used as a treatment for CDI as oral formulations are preferred due to better efficacy in the gut. Therefore, oral metronidazole retains a role as a secondary option based on clinical circumstances.