For odontogenic infections in penicillin-allergic patients, which antibiotic is commonly used?

• A. Amoxicillin
• B. Doxycycline
• C. Ciprofloxacin
• D. Clindamycin

Answer: (D)

When treating odontogenic infections in patients who are allergic to penicillin, the goal is to choose an antibiotic that reliably covers the typical oral pathogens—including anaerobes and oral streptococci—without using a beta-lactam.

Clindamycin fits this need well. It has strong activity against anaerobic bacteria commonly found in dental infections and also covers many Gram-positive cocci, providing good overall coverage for the mixed flora seen in these infections. It also penetrates well into bone and abscessed tissues, helping to control infection at the source. Because it is not a beta-lactam, it avoids the risks associated with penicillin in allergic patients.

The other options don’t align as well with the typical needs. Amoxicillin is a penicillin and would be avoided in someone with a penicillin allergy. Doxycycline can cover some oral pathogens but isn’t as reliable for the anaerobic organisms that drive many odontogenic infections. Ciprofloxacin targets Gram-negative bacteria and has limited anaerobic coverage, making it less ideal for the usual mixed flora of dental infections.