Antibiotic Management for Early (Uncomplicated) Appendicitis in Adults
For adults with early uncomplicated appendicitis undergoing appendectomy, administer a single preoperative dose of broad-spectrum antibiotics 0-60 minutes before surgical incision, with NO postoperative antibiotics required. 1, 2
Preoperative Antibiotic Prophylaxis
The WHO and major surgical societies universally recommend a single preoperative antibiotic dose to decrease wound infections and postoperative intra-abdominal abscesses. 1 This timing window (0-60 minutes before incision) is critical for optimal tissue penetration. 2
Recommended Single-Agent Regimens
The Infectious Diseases Society of America endorses these monotherapy options for mild-to-moderate community-acquired appendicitis: 1
- Ticarcillin-clavulanate
- Cefoxitin
- Ertapenem
- Moxifloxacin
- Tigecycline
Recommended Combination Regimens
Metronidazole PLUS one of the following: 1
- Cefazolin
- Cefuroxime
- Ceftriaxone (maximum 2g daily dose)
- Levofloxacin (only if local E. coli susceptibility ≥90%)
- Ciprofloxacin (only if local E. coli susceptibility ≥90%)
The combination approach ensures adequate anaerobic coverage against Bacteroides fragilis, which cephalosporins alone cannot provide. 1
Critical Antibiotics to AVOID
The IDSA explicitly recommends avoiding: 1
- Ampicillin-sulbactam (inadequate coverage)
- Cefotetan (insufficient activity)
- Clindamycin (resistance concerns)
- Aminoglycosides (toxicity without added benefit)
Postoperative Management for Uncomplicated Cases
No postoperative antibiotics are indicated for uncomplicated appendicitis. 1, 2 This applies when:
- No perforation identified intraoperatively
- No gangrenous changes
- No diffuse purulence
- Complete appendectomy achieved (adequate source control)
Prolonged antibiotic courses provide no additional benefit and increase costs, hospital stays, and antibiotic resistance. 2
Key Pitfalls to Avoid
Do NOT routinely cover Enterococcus in community-acquired appendicitis—this is unnecessary and promotes resistance. 1
Do NOT provide empiric antifungal coverage for Candida in uncomplicated cases. 1
Avoid quinolones unless your institution's E. coli susceptibility data shows ≥90% susceptibility—fluoroquinolone resistance is increasingly problematic. 1
Do NOT confuse uncomplicated with complicated appendicitis—gangrenous or perforated cases require different management (3-5 days maximum postoperatively with adequate source control). 1, 2
Antibiotic-Only Management Consideration
While appendectomy remains first-line treatment, recent evidence suggests antibiotics alone (typically piperacillin-tazobactam or cephalosporin/fluoroquinolone plus metronidazole for 8-15 days) successfully treat approximately 70% of uncomplicated cases initially, with 63-73% remaining symptom-free at one year. 3, 4, 5 However, surgical treatment achieves 93-97% treatment efficacy versus 73% with antibiotics alone. 5
Antibiotic-only approaches have higher failure rates (8.5% during index admission, 19.2% recurrence at one year) and should be reserved for patients who refuse surgery or have prohibitive surgical risk. 5 Patients with appendicoliths, appendiceal diameter >13mm, or mass effect on CT have approximately 40% antibiotic treatment failure rates and should undergo appendectomy. 3