Antibiotic Coverage for Appendicitis
For uncomplicated appendicitis, administer a single preoperative dose of broad-spectrum antibiotics (second- or third-generation cephalosporin like cefoxitin/cefotetan, or piperacillin-tazobactam) with NO postoperative antibiotics required; for complicated appendicitis, initiate IV antibiotics covering enteric gram-negatives and anaerobes (piperacillin-tazobactam, ampicillin-sulbactam, or carbapenems) and discontinue after 24 hours to maximum 3-5 days if adequate source control achieved. 1, 2, 3
Uncomplicated Appendicitis
Preoperative Coverage
- Administer a single dose of broad-spectrum antibiotics 0-60 minutes before surgical incision 3
- Preferred single agents: Cefoxitin, cefotetan, ticarcillin-clavulanate, ertapenem, moxifloxacin, or tigecycline 1, 3
- Combination regimens: Metronidazole plus cefazolin, cefuroxime, ceftriaxone, levofloxacin, or ciprofloxacin 3
- Avoid: Ampicillin-sulbactam, clindamycin, and aminoglycosides for prophylaxis 3
Postoperative Management
- No postoperative antibiotics are indicated for uncomplicated appendicitis in both adults and children 1, 2, 3
- This applies even after successful appendectomy with adequate source control 2, 3
Complicated Appendicitis (Perforated, Gangrenous, Abscess)
Initial Antibiotic Selection
- Broad-spectrum IV antibiotics effective against E. coli and Bacteroides species must be initiated immediately upon diagnosis 1
- Preferred regimens:
- Classic triple therapy for perforation: Ampicillin + clindamycin (or metronidazole) + gentamicin 1
- Alternative combinations: Ceftriaxone-metronidazole or ticarcillin-clavulanate plus gentamicin 1
Duration of Therapy
- Discontinue antibiotics after 24 hours if adequate source control achieved 2, 3
- Maximum duration: 3-5 days postoperatively, even with complicated disease, if source control adequate 1, 2, 3
- Prolonged courses beyond 5 days provide no additional benefit and increase hospital stay 2, 4
- Adequate source control means complete appendectomy with no residual abscess or diffuse purulence 2
Critical Pitfalls to Avoid
- Do NOT routinely cover Enterococcus in community-acquired appendicitis 3
- Do NOT provide empiric antifungal coverage for Candida 3
- Avoid quinolones unless local E. coli susceptibility ≥90% 3
- Metronidazole is NOT needed when using broad-spectrum beta-lactam/beta-lactamase inhibitors or carbapenems 1
- Do NOT confuse gangrenous with perforated appendicitis—only perforated cases with inadequate source control require extended antibiotics 2
Pediatric-Specific Recommendations
Uncomplicated Appendicitis in Children
Complicated Appendicitis in Children
- Broader coverage with piperacillin-tazobactam, ampicillin-sulbactam, or ticarcillin-clavulanate 1, 3
- Early switch to oral antibiotics after 48 hours if clinically improving 1, 2, 3
- Total antibiotic duration <7 days postoperatively 1, 2, 3
- Extended-spectrum antibiotics offer no advantage over narrower-spectrum agents when adequate source control achieved 1
Special Populations
Patients ≥40 Years with Complicated Appendicitis
- Require colonoscopy and interval full-dose contrast-enhanced CT scan due to 3-17% incidence of appendiceal neoplasms 2, 4
- This applies to those treated non-operatively 2, 4
Beta-Lactam Allergy
- Alternative: Moxifloxacin 400mg daily 4
- Ensure local E. coli susceptibility data supports quinolone use 3
Critically Ill or Immunocompromised
- Consider higher dosing: Piperacillin-tazobactam 4.5g IV every 6 hours or 16g/2g continuous infusion 4
- May require extended duration if source control inadequate or delayed 4