First-line antibiotic for odontogenic infection in a patient with no penicillin allergy?

• A. Amoxicillin 500 mg three times daily.
• B. Doxycycline 100 mg twice daily.
• C. Penicillin VK 500 mg four times daily for 5-7 days.
• D. Cephalexin 500 mg four times daily.

Answer: (C)

Penicillin VK is the first-line choice for odontogenic infections in someone with no penicillin allergy because it effectively targets the typical bacteria found in dental abscesses and cellulitis, including viridans group streptococci and anaerobic flora, while staying within a narrow spectrum. Its good oral bioavailability allows the drug to reach gingival tissues and infected pockets, and the 500 mg four times daily dosing for 5–7 days maintains bactericidal levels during the course of treatment. This combination provides reliable efficacy, favorable safety, and cost-effectiveness, with a lower impact on non-target flora.

Other options exist for specific situations—amoxicillin can be used if adherence or tolerability favors a slightly different dosing pattern; doxycycline, cephalexin, or other agents may be chosen if penicillin cannot be used due to allergy or intolerance or if there are particular resistance concerns—but they are not the preferred first-line in an otherwise healthy patient without allergy.