Clinical context (Acute inflammation of the gallbladder, usually calculous — empiric antibiotics when bacterial infection suspected; definitive treatment is early cholecystectomy when surgically feasible (pediatric consensus, Tokyo guidelines principles))
Dose is calculated using the ampicillin component.
Max 2000 mg/dose (ampicillin) · Max 8000 mg/day · Duration: 3–7 days · Uncomplicated with early cholecystectomy: discontinue within 24 h post-op if infection confined to gallbladder (IDSA, SIS Grade 1-A) · gangrene/perforation: 4–7 days after source control (Tokyo TG18 principles)
Enter weight on Kids to calculate doses
Ceftriaxone • i.v. • 50–75 mg/kg/day • 1×/day
Max 2000 mg/day · Duration: 3–7 days · Alternative when ampicillin/sulbactam not used — SIU/HSHS pediatric empiric guideline for cholecystitis
• Ceftriaxone + metronidazole: ampicillin/sulbactam allergy or unavailability; community-acquired cholecystitis per SIU/HSHS 2025 pediatric empiric guidelines.
• Piperacillin/tazobactam: severe infection, healthcare-associated cholecystitis, gangrenous/perforated gallbladder, biliary sepsis, or clinical failure after 48–72 h (SIS higher-risk IAI principles).
• Beta-lactam allergy: ciprofloxacin + metronidazole in selected children when other agents cannot be used — consult ID/pharmacy (SIS Grade 2-B, adult pathway principles).
• Add ampicillin or vancomycin for enterococcal coverage in severe cholangitis/cholecystitis with biliary-enteric anastomosis or healthcare-associated disease if not on piperacillin/tazobactam (SIS, SIU guidelines).
• Oral step-down after cholecystectomy or percutaneous drainage: amoxicillin/clavulanate or ciprofloxacin + metronidazole per culture sensitivities when clinically improving (Brigham pathway principles).
Enter weight on Kids to calculate doses
Metronidazole • i.v. • 10–10 mg/kg/dose • 3×/day
Max 500 mg/dose · Max 1500 mg/day · Duration: 3–7 days · Anaerobic coverage — required with ceftriaxone for biliary anaerobes
Enter weight on Kids to calculate doses
Clinical notes
• Empiric antibiotics are indicated when acute bacterial cholecystitis is suspected (fever, leukocytosis, imaging findings, pericholecystic fluid) — not for uncomplicated biliary colic without inflammation (IDSA 2010, Tokyo TG18).
• Early laparoscopic cholecystectomy is definitive treatment when surgically feasible — typically within 24–72 h of diagnosis in children; do not unduly delay beyond ~72 h in uncomplicated cases (pediatric case series, adult TG18 evidence extrapolated).
• Obtain bile, gallbladder, or blood cultures when feasible at cholecystectomy or drainage — narrow therapy to susceptibility results and de-escalate at 48–72 h (SIS stewardship, IDSA).
• Duration depends on source control and clinical response — discontinue within 24 h post-cholecystectomy for uncomplicated infection confined to the gallbladder; extend to 4–7 days for gangrene, perforation, or delayed source control (IDSA, SIS Grade 1-A, Tokyo TG18).
• Avoid prolonged broad-spectrum antibiotics without culture indication — uncomplicated pediatric cholecystitis after adequate cholecystectomy often requires ≤24 h of postoperative antibiotics; prolonged courses do not reduce complications (SIS, US Pharmacist/IDSA review).
• IDSA — Diagnosis and management of complicated intra-abdominal infection (cholecystitis/cholangitis) (2010)
• SIS — Guidelines on the Management of Intra-Abdominal Infection (2024 update) (2024)
• Tokyo Guidelines — Acute cholecystitis and cholangitis (TG18 principles) (2018)
