Prophylactic Antibiotics

Key Principles:

• Timing is critical: Antibiotic should be given within 60 minutes before incision (vancomycin: within 120 minutes).

• Single-dose is often sufficient: In clean surgeries, one preoperative dose is typically enough unless prolonged surgery or excessive bleeding occurs.

• Redosing: Required if surgery lasts >2 half-lives of the drug or there is excessive blood loss (>1500 mL).

Commonly Used Antibiotics:

• Cefazolin (1st generation cephalosporin): Most commonly used

• Vancomycin: Used in MRSA risk or beta-lactam allergy

• Clindamycin: Alternative for beta-lactam allergy

Special Considerations:

• In trauma or contaminated wounds: Broader spectrum or prolonged antibiotics may be indicated

• In open fractures: Follow Gustilo classification to guide antibiotic type and duration
  Type I/II: 1st gen cephalosporin
  Type III: Add aminoglycoside

Implant-related Surgery:

• Stringent prophylaxis is key (arthroplasty, internal fixation)

• May extend prophylaxis up to 24 hours post-op (but not recommended beyond that in routine cases)

Avoid Overuse:

• Prolonged or unnecessary antibiotics increase risk of resistance and C. difficile infection