Amoxicillin-Clavulanate Dosing for Cat Bites
For cat bite treatment, amoxicillin-clavulanate should be dosed at 875/125 mg twice daily (BID), not three times daily (TID). 1
Guideline-Based Dosing Recommendation
The Infectious Diseases Society of America (IDSA) 2014 guidelines explicitly recommend amoxicillin-clavulanate 875/125 mg BID as the first-line oral therapy for animal bites, including cat bites. 1 This represents the most current and authoritative guidance from the highest-quality source available.
- The 2005 IDSA guidelines also listed both 500/875 mg BID and 500 mg TID as options, but the 2014 update standardized the recommendation to 875/125 mg BID only. 1
- The FDA labeling confirms that amoxicillin-clavulanate tablets "may be taken every 8 hours or every 12 hours, depending on the dose prescribed," supporting both dosing intervals as pharmacologically appropriate. 2
Clinical Rationale for BID Dosing
Cat bites carry particularly high infection risk and require robust antimicrobial coverage:
- Cat bites have a 75% prevalence of Pasteurella multocida compared to 50% in dog bites. 1
- They demonstrate a 65% prevalence of anaerobes versus 50% in dog bites. 1
- Cat bite wounds have the greatest risk of infection among all animal bites, especially hand wounds. 3
- Infection rates in untreated cat bites can reach 67% (4 of 6 patients in placebo group), compared to 0% with prophylactic antibiotics. 4
Pharmacokinetic Support
The higher-dose BID regimen (875/125 mg) provides superior pharmacodynamic parameters:
- Tissue concentrations at 5 and 8 hours are significantly higher with 1g BID dosing (0.7-1.8 μg/g) compared to 500mg TID dosing (0.06-0.7 μg/g). 5
- Time above MIC (T>MIC) values are greater with the BID regimen when MIC is 1 μg/mL (50-66% vs. 40-52%). 5
- Maximum tissue inhibitory quotients are superior with the 1g BID dose against common pathogens including S. pneumoniae, H. influenzae, and M. catarrhalis. 5
Important Clinical Caveats
- Early prophylactic therapy (within 12-24 hours) is critical for preventing infection, particularly in high-risk wounds involving the hand, face, or puncture wounds. 1, 6
- Duration should be 3-5 days for prophylaxis or early preemptive therapy. 1
- Each dose should be taken with food to reduce gastrointestinal upset. 2
- The 875/125 mg BID formulation provides equivalent or superior coverage compared to TID dosing while improving compliance with fewer daily doses. 5