What medications can be used for prophylaxis in appendectomy?

Antibiotic Prophylaxis for Appendectomy

Ceftriaxone (Option B) can be used for appendectomy prophylaxis, though it is not the preferred first-line agent according to current guidelines.

First-Line Recommendations

The optimal prophylaxis for appendectomy is cefazolin (a first-generation cephalosporin) alone or combined with metronidazole, not cephalexin, ceftriaxone, metronidazole alone, or vancomycin. 1

• The WHO 2024 Essential Medicines guidelines specifically recommend cefazolin ± metronidazole as first-line prophylaxis for GI surgery including appendectomy 1
• Australian Therapeutic Guidelines (2019) similarly recommend cefazolin plus metronidazole, or alternatively cefoxitin as single therapy 1
• A single preoperative dose of 2g IV cefazolin given 0-60 minutes before surgical incision is the standard approach for uncomplicated appendicitis 1

Analysis of the Given Options

Option A: Cephalexin - NOT APPROPRIATE

• Cephalexin is an oral first-generation cephalosporin and is not used for surgical prophylaxis
• Surgical prophylaxis requires IV administration to achieve adequate tissue concentrations during the procedure 1

Option B: Ceftriaxone - ACCEPTABLE BUT NOT PREFERRED

• For complicated appendicitis in children, ceftriaxone-metronidazole is an acceptable alternative combination 1
• The 2024 WHO guidelines explicitly note that "ceftriaxone is often inappropriately used as first-line option in many LMICs and did not prioritize it" 1
• Clinical studies from 1988 showed ceftriaxone 1g IV at induction was effective for appendectomy prophylaxis with infection rates of 6.1-11.1% in acute appendicitis 2
• Third-generation cephalosporins should not be used as first-line when first-generation options are available, to preserve antimicrobial stewardship 1

Option C: Metronidazole - INADEQUATE ALONE

• Metronidazole alone is inadequate for appendectomy prophylaxis as it lacks activity against gram-negative aerobes and staphylococci that commonly cause surgical site infections 1
• Metronidazole must be combined with a cephalosporin (cefazolin or ceftriaxone) for adequate coverage 1

Option D: Vancomycin - NOT INDICATED

• Vancomycin is reserved for specific situations: documented beta-lactam allergy, known MRSA colonization, or reoperation in units with high MRSA prevalence 1
• It is not indicated for routine appendectomy prophylaxis 1

Critical Clinical Pitfalls

• Do not prolong antibiotics beyond 3-5 days in complicated cases with adequate source control 1
• For complicated appendicitis, preoperative cefazolin + metronidazole is recommended, with postoperative antibiotics for 24 hours to maximum 3-5 days 1
• Avoid using third-generation cephalosporins when narrower-spectrum options are effective, to prevent antimicrobial resistance 1

The correct answer from the options provided is B (Ceftriaxone), though it represents a second-line choice rather than optimal prophylaxis.