Antibiotic Prescription for Dog Bite
Amoxicillin-clavulanate is the first-line antibiotic for dog bite wounds, dosed at 875 mg/125 mg every 12 hours for adults (or 45 mg/kg/day divided every 12 hours for children), for 3-5 days for prophylaxis or 7-14 days for established infection. 1, 2
First-Line Therapy
Amoxicillin-clavulanate is strongly recommended by the Infectious Diseases Society of America as the first-line agent because it provides comprehensive coverage against both aerobic and anaerobic bacteria commonly found in dog bite wounds 1
Dog bite wounds are polymicrobial, containing an average of 5 different bacterial species including Pasteurella species (found in 20-50% of wounds), Staphylococcus aureus, Streptococcus species, and anaerobes like Bacteroides and Fusobacterium 2, 3
The combination specifically targets Pasteurella multocida, which can cause serious infection with severe complications and is isolated in 20-30% of dog bite wounds 4
Dosing Regimens
Adults: 875 mg/125 mg every 12 hours or 500 mg/125 mg every 8 hours 1, 5
Pediatric patients: 45 mg/kg/day divided every 12 hours 1
Duration: 3-5 days for prophylactic therapy in high-risk wounds; 7-14 days for established infections depending on severity 1, 2
Alternative Options for Penicillin Allergy
Non-anaphylactic penicillin allergy: Doxycycline 100 mg twice daily (if ≥8 years old), which has excellent activity against Pasteurella multocida 1, 2
Severe penicillin allergy: Fluoroquinolones (e.g., ciprofloxacin) plus metronidazole, though fluoroquinolones should generally be avoided in children 1
Alternative oral regimens include penicillin VK plus dicloxacillin, though this requires twice-daily dosing of two separate medications 2, 6
High-Risk Wounds Requiring Prophylactic Antibiotics
Category 3 dog bites (full-thickness skin penetration) require preemptive antimicrobial therapy due to high infection risk 1
Hand wounds are at significantly higher risk for complications and should be treated more aggressively 2
Immunocompromised patients or those with advanced liver disease warrant prophylactic antibiotics even for minor wounds 2
Cat bite wounds on the hand have the greatest risk of infection and should always receive prophylactic antibiotics 4
Critical Management Pitfalls
Failure to recognize polymicrobial nature: Using antibiotics with inadequate coverage against Pasteurella species (such as first-generation cephalosporins alone or dicloxacillin alone) leads to treatment failure 2, 6
Inadequate anaerobic coverage: Simple penicillin prophylaxis has been shown to fail in preventing dog bite infections, with infection rates similar to placebo 7
Meta-analyses demonstrate that appropriate antibiotics reduce infection risk in dog bite wounds by approximately 44%, but only when proper spectrum coverage is used 1
Essential Adjunctive Management
Copious irrigation and cautious debridement of the wound are critical components of care 1
Avoid primary wound closure except for facial wounds, as closure increases infection risk 1
Tetanus prophylaxis should be administered if not vaccinated within the past 10 years, with Tdap preferred over Td if not previously given 1, 2
Rabies post-exposure prophylaxis requires consultation with local health officials based on local epidemiology 1, 2
Evidence Quality Note
The recommendation for amoxicillin-clavulanate comes from strong Infectious Diseases Society of America guidelines (2014) and is supported by consistent evidence showing superior coverage of the polymicrobial flora in dog bite wounds compared to alternatives 1, 2, 3, 4