Clindamycin is Correctly Paired with Clostridioides difficile Diarrhea
The correct answer is B: Clindamycin is definitively associated with Clostridioides difficile diarrhea, as explicitly stated in FDA labeling and multiple clinical guidelines. 1
Direct Evidence from FDA Drug Labeling
The FDA-approved prescribing information for clindamycin carries a boxed warning specifically for Clostridioides difficile-associated diarrhea (CDAD), stating that "Clostridioides difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including clindamycin hydrochloride, and may range in severity from mild diarrhea to fatal colitis." 1 This represents the highest level of safety warning the FDA can issue for a medication.
- Clindamycin is explicitly recognized as a major risk factor for C. difficile infection in clinical practice, with guidelines noting that "risk factors include recent exposure to health care facilities or antibiotics, especially clindamycin." 2
Why the Other Options Are Incorrect
Vancomycin (Option A)
- Vancomycin is actually the treatment of choice for C. difficile infection, not a cause of gastrointestinal intolerance. 3, 4
- Guidelines recommend vancomycin 125 mg four times daily for 10 days as first-line therapy for initial CDI episodes. 4
Erythromycin (Option C)
- Erythromycin's FDA labeling warns of hepatotoxicity (liver dysfunction) and QT prolongation, not nephrotoxicity. 5
- While erythromycin can cause C. difficile infection like other antibiotics, its characteristic adverse effect is cardiac arrhythmia and hepatic dysfunction. 5
Aminoglycosides (Option D)
- Aminoglycosides are classically associated with nephrotoxicity and ototoxicity, not infusion reactions. 3
- The infusion reactions described (flushing, rash, pruritus) are characteristic of vancomycin's "red man syndrome," not aminoglycosides.
Clinical Significance of Clindamycin-Associated CDI
Clindamycin disrupts normal colonic flora, allowing C. difficile overgrowth and toxin production. 1
- C. difficile produces toxins A and B that contribute to CDAD development, with hypertoxin-producing strains causing increased morbidity and mortality. 1, 5
- The infection can range from mild diarrhea to fatal colitis requiring colectomy. 1
- CDAD must be considered in all patients presenting with diarrhea following clindamycin use, as it can occur up to two months after antibiotic administration. 1
Critical Management Points
- If CDAD is suspected or confirmed in a patient on clindamycin, the drug should be discontinued unless no alternative exists. 1
- Treatment requires appropriate fluid/electrolyte management, protein supplementation, and antibiotic therapy directed against C. difficile (vancomycin or fidaxomicin). 1, 4
- Rare cases of C. difficile-related colitis have been reported even with topical clindamycin, though the risk appears low. 3