Organism-Specific Therapeutic Regimens
Organism-specific therapeutic regimens for appendicitis in adults are outlined below, including those for anaerobic organisms (including Bacteroides fragilis, Clostridium spp, and Prevotella spp), aerobic gram-negative bacilli (including Escherichia coli, Klebsiella spp, and Proteus mirabilis), Pseudomonas aeruginosa, streptococci, enterococci, and mixtures of aerobes and anaerobes. [1, 2, 3, 4]
See Appendicitis: Avoiding Pitfalls in Diagnosis, a Critical Images slideshow, to help make an accurate diagnosis.
Anaerobic organisms (including Bacteroides fragilis, Clostridium spp, Prevotella spp)
See the list below:
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Clindamycin 600 mg IV q8h or
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Metronidazole 500 mg IV q8h or
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Ertapenem 1 g IV daily or
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Ampicillin-sulbactam 3 g IV q6h or
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Ticarcillin-clavulanate 3.1 g IV q4-6h or
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Ceftolozane/tazobactam 1.5 g IV q8h plus metronidazole 500 mg IV q8h
Aerobic gram-negative bacilli (including Escherichia coli, Klebsiella spp, Proteus mirabilis)
See the list below:
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Aztreonam 1-2 g IV q8h or
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Ampicillin 2 g IV q4h for or
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Ciprofloxacin 400 mg IV q12h or
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Ertapenem 1 g IV daily or
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Levofloxacin 750 mg IV q24h or
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Gentamicin 5-7 mg/kg IV q24h or
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Cefoxitin 2g IV q8h or
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Cefotetan 2 g IV q12h or
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Cefotaxime 1-2 g IV q6-8h or
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Ceftriaxone 1-2g IV q24h or
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Ceftolozane/tazobactam 1.5 g IV q8h plus metronidazole 500 mg IV q8h
Pseudomonas aeruginosa
See the list below:
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Aztreonam 1-2 g IV q8h or
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Ciprofloxacin 400 mg IV q12h or
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Piperacillin-tazobactam 4.5 g IV q6h or
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Doripenem 500 mg IV q8h or
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Imipenem-cilastatin 500 mg IV q6h or
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Meropenem 1 g IV q8h or
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Ceftolozane/tazobactam 1.5 g IV q8h plus metronidazole 500 mg IV q8h
Streptococci and enterococci
See the list below:
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Ampicillin-sulbactam 3 g IV q6h or
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Ticarcillin-clavulanate 3.1 g IV q4-6h or
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Piperacillin-tazobactam 3.375-4.5 g IV q6-8h or
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Doripenem 500 mg IV q8h or
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Imipenem-cilastatin 500 mg IV q6h or
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Meropenem 1 g IV q8h or
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Ceftolozane/tazobactam 1.5 g IV q8h plus metronidazole 500 mg IV q8h
Mixture of aerobes and anaerobes
See the list below:
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Cefoxitin 2g IV q8h or
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Cefotetan 2 g IV q12h or
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Ticarcillin-clavulanate 3.1 g IV q4-6h or
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Piperacillin-tazobactam 3.375-4.5 g IV q6-8h or
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Ampicillin-sulbactam 3 g IV q6h or
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Doripenem 500 mg IV q8h or
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Imipenem-cilastatin 500 mg IV q6h or
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Meropenem 1 g IV q8h or
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Ertapenem 1 g IV daily or
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Moxifloxacin 400 mg IV q24h