What medication is recommended for a healthy patient with no significant medical history after a dog bite?

Dog Bite Medication Management

For a healthy patient with no significant medical history after a dog bite, amoxicillin-clavulanate 875/125 mg twice daily for 3-5 days is the recommended antibiotic for prophylaxis if high-risk features are present, or 7-10 days if infection is already established. 1, 2, 3

Antibiotic Prophylaxis Decision Algorithm

Determine if prophylactic antibiotics are indicated based on these high-risk criteria:

• Moderate to severe injuries 1
• Puncture wounds (especially from cats, but applies to dogs) 4
• Hand wounds (higher infection and functional complication risk) 1, 3
• Wounds with edema of the affected area 1
• Injuries that may have penetrated periosteum or joint capsule 1, 3
• Facial wounds requiring primary closure 1
• Wounds presenting >8 hours after injury 5

For healthy patients with minor, superficial wounds not meeting these criteria, prophylactic antibiotics may not be necessary, though the baseline infection risk is approximately 16% without antibiotics. 6

First-Line Antibiotic Selection

Amoxicillin-clavulanate is the preferred agent because:

• Provides comprehensive coverage against polymicrobial flora (average 5 bacterial species per wound, 60% mixed aerobic/anaerobic) 5, 2
• Covers Pasteurella species (isolated from 50% of dog bites) 5, 2
• Covers Staphylococci and Streptococci (found in ~40% of dog bites) 5
• Covers anaerobes including Bacteroides, Fusobacteria, and Peptostreptococci 5

Dosing: 875/125 mg twice daily 1, 2, 3

Alternative Antibiotics for Penicillin Allergy

If the patient cannot tolerate amoxicillin-clavulanate:

• Doxycycline 100 mg twice daily (excellent activity against Pasteurella multocida) 1, 3
• Fluoroquinolones with additional anaerobic coverage (such as moxifloxacin) 1, 3

Avoid: First-generation cephalosporins, macrolides, or clindamycin alone have poor activity against Pasteurella multocida. 3

Treatment Duration

• Prophylaxis for high-risk wounds: 3-5 days 1
• Established soft tissue infection: 7-10 days 2
• Septic arthritis: 4 weeks 1, 2
• Osteomyelitis: 6 weeks 1, 2

Essential Concurrent Management

Tetanus prophylaxis:

• Administer if not vaccinated within past 10 years (or 5 years for dirty wounds) 1, 3
• Tdap preferred over Td if not previously given 1, 3

Rabies assessment:

• Consult local health officials regarding rabies risk 1, 3
• If dog is healthy and available, confine and observe for 10 days without administering rabies vaccine during observation 1, 3
• If dog cannot be observed or develops signs of illness, initiate rabies post-exposure prophylaxis (immunoglobulin + vaccine on days 0,3,7,14) 3, 4

Wound care:

• Copious irrigation with sterile normal saline using 20-mL or larger syringe 3, 4
• Debride devitalized tissue carefully 1, 3
• Primary closure for facial wounds only (optimal cosmetic results due to rich vascular supply) 1, 3
• Non-facial wounds should be left open or loosely approximated 1, 2

Mandatory Follow-Up

All patients require reassessment within 48-72 hours to:

• Assess for signs of infection (increasing pain, redness, swelling, purulent drainage) 1, 3
• Evaluate wound healing progress 1
• Consider hospitalization if fever, systemic symptoms, rapidly spreading erythema, lymphangitis, abscess formation, or failure to improve on antibiotics 2

Common Pitfalls to Avoid

• Inadequate irrigation increases infection risk significantly 3
• Using inappropriate antibiotics without Pasteurella coverage (the organism causes rapidly developing cellulitis with serosanguineous drainage within 12-24 hours) 2
• Closing non-facial wounds primarily (increases infection risk) 1, 2
• Overlooking hand wounds (require special attention due to higher complication rates) 1, 3
• Failing to address tetanus and rabies prophylaxis 3