What is the recommended amoxicillin dose (mg/kg per dose) for prophylaxis in a child with a moderate‑to‑severe dog bite?

Amoxicillin-Clavulanate Dosing for Pediatric Dog Bite Prophylaxis

For moderate-to-severe dog bites in children requiring antibiotic prophylaxis, use amoxicillin-clavulanate at 45 mg/kg/day of the amoxicillin component divided into two or three doses, with a maximum single dose of 875 mg. 1

Indications for Prophylactic Antibiotics

Preemptive antimicrobial therapy for 3–5 days is recommended for pediatric dog bites when any of the following criteria are met: 1

• Moderate to severe injuries, especially to the hand or face 1
• Puncture wounds that may have penetrated the periosteum or joint capsule 1
• Immunocompromised status or asplenia 1
• Advanced liver disease 1
• Preexisting or resultant edema of the affected area 1

Specific Dosing Regimen

The standard pediatric dose is 45 mg/kg/day of the amoxicillin component, which can be administered as: 2, 3

• Twice-daily dosing: 22.5 mg/kg per dose every 12 hours 2, 3
• Three-times-daily dosing: 15 mg/kg per dose every 8 hours 3

The maximum single dose is 875 mg (adult dose), regardless of calculated weight-based dose 1

For a typical school-age child weighing 20 kg, this translates to approximately 450 mg twice daily or 300 mg three times daily. 2, 3

Rationale for Amoxicillin-Clavulanate

Amoxicillin-clavulanate is the first-line agent because it provides coverage against the polymicrobial flora of dog bites: 1

• Pasteurella multocida (present in 20–30% of dog bite wounds) 4
• Staphylococcus aureus and streptococci 1
• Anaerobic organisms 1
• β-lactamase-producing organisms that would resist amoxicillin alone 3

The clavulanate component is essential because it inhibits β-lactamases produced by many oral flora organisms. 3

Treatment Duration

Prophylactic therapy should be given for 3–5 days for high-risk wounds without established infection. 1, 5

If infection develops, extend treatment to 7–10 days for uncomplicated wound infections. 5

Alternative Regimens for Penicillin Allergy

For children with non-anaphylactic penicillin allergy: 2

• Cefuroxime 30 mg/kg/day divided twice daily (maximum 500 mg per dose) 1

For children with IgE-mediated (Type I) penicillin allergy: 1

• Doxycycline 2–4 mg/kg/day divided twice daily (maximum 100 mg per dose) for children ≥8 years 1
• Clindamycin 10–20 mg/kg/day divided three times daily (maximum 300 mg per dose) plus trimethoprim-sulfamethoxazole 8–10 mg/kg/day (TMP component) divided twice daily 1

Note that clindamycin alone misses Pasteurella multocida, so combination therapy is required. 1

Common Pitfalls to Avoid

Do not use amoxicillin alone for dog bite prophylaxis—the clavulanate component is essential for β-lactamase-producing organisms commonly found in animal oral flora. 3, 4

Do not prescribe prophylactic antibiotics for low-risk wounds (superficial abrasions presenting within 12–24 hours in immunocompetent patients without hand/face involvement), as the infection rate is low (5–25%) and good wound care is most important. 5, 6

Ensure tetanus prophylaxis is current (within 10 years for clean wounds, within 5 years for contaminated wounds). 1

Assess rabies risk and consult local health officials to determine if postexposure prophylaxis is needed. 1

Evidence Strength

The recommendation for amoxicillin-clavulanate is graded as strong with moderate-quality evidence by the Infectious Diseases Society of America. 1 A Cochrane review found that prophylactic antibiotics significantly reduce infection rates in hand bites (NNT = 4), though evidence for routine prophylaxis in all dog bites is limited. 7 The key is risk stratification—selective use based on wound characteristics and patient factors rather than universal prophylaxis. 5