In penicillin-allergic patients requiring dental prophylaxis, which antibiotic is commonly used as an alternative?

• A. Amoxicillin
• B. Doxycycline
• C. Clindamycin 600 mg orally before the procedure
• D. Cefdinir

Answer: (C)

When penicillin cannot be used, the prophylaxis choice needs to cover the same oral bacteria that can enter the bloodstream during dental work, especially viridans streptococci and oral anaerobes, and it should act quickly enough to protect during the procedure. Clindamycin fits best because it has strong activity against these organisms, good oral bioavailability, and excellent tissue penetration. A single 600 mg dose taken by mouth about an hour before the procedure provides effective protection against endocarditis risk in penicillin-allergic patients undergoing dental prophylaxis.

Amoxicillin and cefdinir are penicillin-family antibiotics and are best avoided in true penicillin allergy due to cross-reactivity concerns. Doxycycline is an alternative but is not as consistently preferred for dental prophylaxis because of variability in resistance patterns and dosing considerations.