Best Antibiotic for Cat Bite
Amoxicillin-clavulanate 875/125 mg twice daily is the first-line antibiotic for cat bites in healthy adults without drug allergies 1, 2, 3.
Primary Recommendation
The IDSA guidelines explicitly list amoxicillin-clavulanate as the oral antibiotic of choice for animal bites 1. This recommendation is consistently supported across multiple high-quality sources 2, 3, 4, 5. The standard adult dosing is 875/125 mg twice daily for prophylaxis or treatment 1.
Why Amoxicillin-Clavulanate?
Cat bites create deep puncture wounds that carry particularly high infection risk—higher than dog bites 2, 3. The key pathogen is Pasteurella multocida, isolated in over 50% of cat bite wounds 4, 5. Cat bites also introduce:
- Streptococcus species
- Staphylococcus aureus
- Anaerobic bacteria 6
Amoxicillin-clavulanate provides broad coverage against all these organisms 1, 5. The clavulanate component is critical because it overcomes beta-lactamase resistance that would render amoxicillin alone ineffective.
When to Prescribe
Antibiotic prophylaxis should be considered for all cat bites, particularly those with:
- Puncture wounds (the typical cat bite pattern)
- Hand involvement (highest infection risk)
- Any wound requiring closure
- Presentation >8 hours after injury 2, 3
Cat bites to the hand have the greatest risk of infection among all bite wounds 4. Given this high-risk profile, the threshold for prescribing prophylaxis should be low.
Treatment Duration
Standard course is 7-10 days for prophylaxis or established infection 1, 3.
Alternative Options (If Allergic)
The IDSA guideline provides alternatives when amoxicillin-clavulanate cannot be used 1:
- Doxycycline 100 mg twice daily - excellent activity against P. multocida, though some streptococci may be resistant
- Moxifloxacin 400 mg daily - provides monotherapy coverage including anaerobes
- Combination therapy: Penicillin plus dicloxacillin, or a second-generation cephalosporin (cefuroxime) plus metronidazole
Critical Pitfalls to Avoid
Do not use clindamycin alone - it misses P. multocida despite good activity against staphylococci, streptococci, and anaerobes 1.
Do not use first-generation cephalosporins (cephalexin) - inadequate coverage for the polymicrobial nature of cat bites.
Do not use typical empiric skin infection antibiotics - Pasteurella is resistant to many standard agents used for cellulitis 5.
Additional Wound Management
Beyond antibiotics, ensure:
- Copious irrigation with normal saline
- Wound exploration for foreign bodies and deep structure involvement
- Assessment of neurovascular function
- Tetanus status verification
- Rabies risk evaluation (though domestic cat bites rarely require rabies prophylaxis if the cat is available for observation) 2, 3
Primary closure is generally avoided for cat bites due to the deep puncture nature and high infection risk, unless cosmetically critical (facial wounds) 1, 3.