What is the recommended antibiotic regimen for complicated appendicitis according to Philippine guidelines?

Antibiotic Regimen for Complicated Appendicitis: Philippine Context

For complicated appendicitis in the Philippines, use the same evidence-based regimens recommended by international guidelines, as no specific Philippine guidelines were identified in the provided evidence. The most appropriate regimens are based on the 2020 WSES Jerusalem Guidelines and 2010 SIS/IDSA guidelines.

Recommended Antibiotic Regimens for Adults

First-Line Options for Community-Acquired Complicated Appendicitis

For non-critically ill adult patients with complicated appendicitis, the following regimens are recommended: 1

• Amoxicillin-clavulanate 1.2–2.2 g IV every 6 hours
• Ceftriaxone 2 g IV every 24 hours + Metronidazole 500 mg IV every 6 hours
• Cefotaxime 2 g IV every 8 hours + Metronidazole 500 mg IV every 6 hours

Alternative Regimens

For patients with beta-lactam allergy: 1

• Ciprofloxacin 400 mg IV every 8 hours + Metronidazole 500 mg IV every 6 hours
• Moxifloxacin 400 mg IV every 24 hours

For patients at risk for ESBL-producing organisms: 1

• Ertapenem 1 g IV every 24 hours
• Tigecycline 100 mg initial dose, then 50 mg IV every 12 hours

Broader-Spectrum Options

For more severe community-acquired infections or when higher coverage is needed: 1

• Piperacillin-tazobactam 3.375 g IV every 6 hours
• Ticarcillin-clavulanate 3.1 g IV every 6 hours
• Carbapenems (imipenem, meropenem, or ertapenem)

Pediatric Dosing for Complicated Appendicitis

Acceptable broad-spectrum regimens for children include: 1

• Ampicillin-sulbactam 200 mg/kg/day (of ampicillin component) IV every 6 hours
• Piperacillin-tazobactam 200–300 mg/kg/day (of piperacillin component) IV every 6–8 hours
• Ceftriaxone 50–75 mg/kg/day IV every 12–24 hours + Metronidazole 30–40 mg/kg/day IV every 8 hours
• Cefotaxime 150–200 mg/kg/day IV every 6–8 hours + Metronidazole 30–40 mg/kg/day IV every 8 hours
• Ertapenem: 15 mg/kg twice daily (not to exceed 1 g/day) for ages 3 months to 12 years; 1 g/day for age ≥13 years

For children with severe beta-lactam allergies: 1

• Ciprofloxacin 20–30 mg/kg/day IV every 12 hours + Metronidazole 30–40 mg/kg/day IV every 8 hours
• Aminoglycoside-based regimen (gentamicin 3–7.5 mg/kg/day) with metronidazole

Duration of Antibiotic Therapy

Postoperative Duration

For complicated appendicitis with adequate source control, antibiotics should NOT be prolonged beyond 3–5 days postoperatively. 1 The 2015 STOP-IT trial demonstrated that fixed-duration therapy (approximately 4 days) had similar outcomes to longer courses (approximately 8 days). 1

In children with complicated appendicitis, early switch to oral antibiotics after 48 hours is recommended, with total therapy duration less than 7 days. 1

For Uncomplicated Appendicitis

A single preoperative dose of broad-spectrum antibiotics is sufficient for uncomplicated appendicitis; postoperative antibiotics are NOT recommended. 1

Important Clinical Considerations

What NOT to Use

Avoid the following agents due to resistance patterns: 1

• Ampicillin-sulbactam (high E. coli resistance rates)
• Cefotetan and clindamycin (increasing Bacteroides fragilis resistance)

Coverage Considerations

Empiric enterococcal coverage is NOT necessary for community-acquired complicated appendicitis. 1

Empiric antifungal therapy is NOT recommended for community-acquired complicated appendicitis. 1

Aminoglycosides are not recommended for routine use in adults due to toxicity, though less toxic alternatives are equally effective. 1 However, aminoglycoside-based regimens (gentamicin, ampicillin, and clindamycin or metronidazole) have been successfully used for decades in children. 1

Local Resistance Patterns

Quinolones should not be used unless local hospital surveillance indicates ≥90% E. coli susceptibility to quinolones. 1 Quinolone-resistant E. coli has become common in some communities, making this an important consideration in the Philippine setting where resistance patterns may vary by region.

Moxifloxacin should be avoided for patients likely to harbor B. fragilis if they received quinolone therapy within 3 months, as organisms are likely quinolone-resistant. 1

Common Pitfalls to Avoid

1. Do not routinely add gentamicin empirically to ceftriaxone-metronidazole regimens, as this does not reduce postoperative abscess rates compared to changing antibiotics based on clinical response. 2

2. Do not prolong antibiotics beyond 3–5 days in adequately source-controlled complicated appendicitis, as this increases costs and antimicrobial resistance without improving outcomes. 1

3. Do not use broad-spectrum agents with anti-pseudomonal activity (like piperacillin-tazobactam or carbapenems) for mild-to-moderate community-acquired infections when narrower-spectrum agents are appropriate, as this facilitates acquisition of resistant organisms. 1

4. Ensure adequate dosing of beta-lactam antibiotics if undrained intra-abdominal abscesses may be present. 1