Appendicitis – Emergency Department and Inpatient – Antibiotic Recommendations

Appendicitis – Emergency Department and Inpatient – Antibiotic Recommendations

Antibiotic Recommendations

General Principles

  • Empiric antibiotics are based on the most likely pathogens and local susceptibilities.
  • Empiric treatment with ceftriaxone/metronidazole is appropriate for most patients with perforated appendicitis. Failure to improve is unlikely due to antibiotic resistance and more likely related to need for source control, however clinicians may consider broadening antibiotics to piperacillin/tazobactam for children without clinical improvement after 3–5 days.
  • Antibiotic duration largely depends on whether and when source control has been attained. Determination of the timing of adequate source control is at the discretion of the treating clinicians. For example, this may occur at time of initial procedure if there is complete drainage, or once drain output ceases if there is prolonged post-procedure drainage.
    • Acute non-perforated appendicitis does not require antibiotics post-operatively.
    • Treat perforated appendicitis with or without abscess after source control for no more than 5 days.
    • Duration of antibiotics is not well defined for perforated appendicitis without source control. Use factors such as symptom improvement, fever resolution, and reduction in size of the abscess to guide. Total duration of 10–14 days is reasonable.
    • Children managed non-operatively for acute, non-perforated appendicitis may receive 10 days of antibiotics.
  • Consider ID consult for children who are still febrile and symptomatic on post-operative day 5–7.
Indication First-Line Therapy Allergy to First-Line β-Lactam
Assess Need for Alternative
  • Acute Appendicitis Diagnosis, Preoperative
  • and
  • Acute Non-Perforated Appendicitis, Operative
  • Ceftriaxone, IV
    • 75 mg/kg/dose once
    • Max: 2000 mg/dose
  • and
  • Metronidazole, IV
    • Patients < 80 kg:
      • 30 mg/kg/dose once
      • Max: 1000 mg/dose
    • Patients ≥ 80 kg:
      • 1500 mg once
  • Ciprofloxacin, IV
    • 10 mg/kg/dose once
    • Max: 400 mg/dose
  • and
  • Metronidazole, IV
    • Patients < 80 kg:
      • 30 mg/kg/dose once
      • Max: 1000 mg/dose
    • Patients ≥ 80 kg:
      • 1500 mg once
  • Perforated Appendicitis
  • and
  • Acute Non-Perforated Appendicitis, NON-Operative
  • Ceftriaxone, IV
    • 75 mg/kg/dose every 24 hours
    • Max: 2000 mg/dose
  • and
  • Metronidazole, IV
    • Patients < 80 kg:
      • 30 mg/kg/dose every 24 hours
      • Max: 1000 mg/dose
    • Patients ≥ 80 kg:
      • 1500 mg every 24 hours
  • Ciprofloxacin, IV
    • 10 mg/kg/dose every 12 hours
    • Max: 400 mg/dose
  • and
  • Metronidazole, IV
    • Patients < 80 kg:
      • 30 mg/kg/dose every 24 hours
      • Max: 1000 mg/dose
    • Patients ≥ 80 kg:
      • 1500 mg every 24 hours
Perforated Appendicitis Not Improving After 3–5 Days
  • Piperacillin/tazobactam, IV
    • Patients ≤ 40 kg:
      • 100 mg piperacillin/kg/dose every 8 hours
      • Max: 3000 mg piperacillin/dose
    • Patients > 40 kg:
      • 3000 mg piperacillin/dose every 6 hours
  • Ertapenem, IV
    • Patients < 13 years:
      • 15 mg/kg/dose every 12 hours
      • Max: 500 mg/dose
    • Patients ≥ 13 years:
      • 1000 mg/dose every 24 hours
    • Consult ID

Transition to Enteral Therapy

  • Antibiotic therapy may be guided by culture results in some cases.
  • Consider discussion with Antimicrobial Stewardship or ID consult for antibiotic recommendations.
  • Perforated Appendicitis
  • and
  • Acute Non-Perforated Appendicitis, NON-Operative
  • Ciprofloxacin, PO
    • 15 mg/kg/dose every 12 hours
    • Max: 500 mg/dose
  • and
  • Metronidazole, PO
    • 10 mg/kg/dose every 8 hours
    • Max: 500 mg/dose
Amoxicillin/clavulanate is generally not preferred due to suboptimal gram-negative coverage, but may be considered for some patients in discussion with Antimicrobial Stewardship or ID.

CHOP Formulary for complete drug information.