What is a major adverse effect associated with clindamycin in dental practice?

• A. Photosensitivity.
• B. Nephrotoxicity.
• C. C. difficile–associated diarrhea.
• D. Ototoxicity.

Answer: (C)

Clindamycin’s most notable safety concern in dental practice is antibiotic-associated colitis caused by Clostridioides difficile. The drug’s broad anaerobic activity can disrupt the normal gut microbiota, allowing C. difficile to overgrow and release toxins that inflame and damage the colon lining. This toxin-mediated process can produce diarrhea that ranges from mild to severe and potentially life-threatening, making C. difficile–associated diarrhea the major adverse effect to watch for after clindamycin use.

Other listed adverse effects aren’t typical of clindamycin. Nephrotoxicity and ototoxicity are more associated with certain other antibiotic classes, and photosensitivity is more characteristic of drugs like tetracyclines. If diarrhea develops during therapy—especially with abdominal pain, fever, or dehydration—it's important to contact a clinician promptly, as management may involve stopping the antibiotic and treating the C. difficile infection with appropriate therapy.