Treatment Duration for Cat Bite Prophylaxis
For cat bite prophylaxis, treat with antibiotics for 3-5 days, with most guidelines recommending a 5-day course of amoxicillin-clavulanate as the standard duration. 1, 2
Evidence-Based Duration Recommendations
Standard Prophylaxis Duration
- The most definitive evidence comes from a prospective, double-blind, placebo-controlled trial that used oxacillin 500 mg four times daily for 5 days, which significantly reduced infection rates (0% vs 67% in placebo group, P=0.045). 2
- The IDSA guidelines recommend 7-10 days of treatment for cutaneous infections from animal bites, though this applies more to established infections rather than pure prophylaxis. 1
- For prophylactic therapy specifically, a 3-5 day course is standard practice, with 5 days being most commonly recommended based on the landmark oxacillin study. 2
Extended Duration for Special Circumstances
- If infection develops despite prophylaxis, extend treatment to 7-10 days for uncomplicated soft tissue infections. 1, 3
- For diabetic patients with cat bite infections, treat for 1-2 weeks for mild soft tissue infections, extending to 3-4 weeks if the infection is extensive or resolving slowly. 3
- Deep structure involvement requires significantly longer courses: 3-4 weeks for septic arthritis and 4-6 weeks for osteomyelitis. 1
Clinical Context and Rationale
Why Cat Bites Require Aggressive Prophylaxis
- Cat bites have a 20-80% infection rate compared to only 3-18% for dog bites, making prophylactic antibiotics essential rather than optional. 4
- Pasteurella multocida is isolated in over 50% of cat bite wounds and can cause serious infection with severe complications. 5, 4
- Hand wounds from cat bites carry the greatest infection risk and warrant prophylaxis regardless of initial appearance. 5
Antibiotic Selection
- Amoxicillin-clavulanate remains first-line, with P. multocida showing 100% susceptibility in recent surveillance studies. 4
- The 5-day duration from the oxacillin study 2 translates directly to modern amoxicillin-clavulanate regimens (500-875 mg twice daily). 1, 3
Common Pitfalls to Avoid
- Do not underestimate small puncture wounds from cat bites—even tiny external wounds can cause deep infections including osteomyelitis. 6
- Do not use first-generation cephalosporins or clindamycin alone, as they miss P. multocida coverage. 1
- Do not stop antibiotics early even if the wound looks clean—cat bite infections can develop insidiously over 24-48 hours. 7
- Ensure 24-hour follow-up (phone or in-person) for all cat bite patients receiving prophylaxis to catch early infection. 1, 3