Beta-lactam Antibiotic Regimen for Peritonitis

First-line Beta-lactam Options

The World Journal of Emergency Surgery recommends meropenem 1 g every 6 hours administered by extended or continuous infusion for patients with peritonitis, especially in critically ill patients or those with septic shock 1
For non-critically ill, immunocompetent patients with adequate source control, piperacillin/tazobactam 4.5 g every 6 hours (or 16 g/2 g by continuous infusion) is recommended 2, 3
For less severe cases, amoxicillin/clavulanate 2 g/0.2 g every 8 hours is recommended 4

For patients with documented beta-lactam allergy, eravacycline 1 mg/kg every 12 hours is considered 1, 2
For patients at risk for MDR pathogens or ESBLs, imipenem/cilastatin-relebactam 1.25 g every 6 hours by extended infusion is recommended 3

Higher initial loading doses are recommended for beta-lactams in critically ill patients to account for increased volume of distribution 7, 8
Extended or continuous infusions of beta-lactams are preferred to maximize time above MIC, particularly for less susceptible pathogens 7, 8

4 days of therapy is recommended for immunocompetent, non-critically ill patients with adequate source control 1, 2
Up to 7 days of therapy is recommended for immunocompromised or critically ill patients with adequate source control 1, 2

Inadequate initial dosing is common in critically ill patients due to increased volume of distribution and augmented renal clearance 7, 8
Therapeutic drug monitoring should be considered when available, particularly in critically ill patients 8
Source control remains essential; antimicrobial therapy alone is insufficient for complicated intra-abdominal infections 9, 10
Early administration of antibiotics is crucial, especially in patients with septic shock 9, 10