Drug used to treat or prevent infection for soft tissue abscess, cellulitis, and post-surgical periodontal infection is:

• A. Pen VK
• B. Metronidazole
• C. Amoxicillin
• D. Clindamycin

Answer: (A)

The main idea is that many dental infections are caused by the naturally occurring oral flora, especially viridans group streptococci and anaerobic bacteria that reside in the mouth. Penicillin V is a narrow-spectrum penicillin that is highly effective against these organisms when given by mouth. It penetrates soft tissues well, has a favorable safety profile, and is inexpensive, making it a practical first-line option for mild-to-moderate soft tissue abscesses, cellulitis, and post-surgical periodontal infections.

Metronidazole targets anaerobes but doesn’t reliably cover streptococci, so it’s not sufficient as a sole agent for typical odontogenic infections. Amoxicillin offers broader coverage but Penicillin V is preferred for its targeted activity against the main pathogens involved, plus cost and tolerability. Clindamycin serves as an alternative when penicillin cannot be used, but it carries a higher risk of adverse effects like C. difficile infection, so it’s not first-line for these common infections.