What is the recommended piperacillin/tazobactam dosing regimen for children, including neonates and infants, based on weight, infection severity, and renal function?

Piperacillin-Tazobactam Dosing for Pediatric Patients

For children beyond 2 months of age with serious infections, administer piperacillin-tazobactam at 240-300 mg/kg/day (based on the piperacillin component) divided every 6-8 hours, with higher doses and extended infusions preferred for critically ill patients or infections caused by organisms with elevated MICs. 1

Standard Dosing by Age Group

Neonates and Young Infants (<2 months)

• Postmenstrual age ≤30 weeks: 100 mg/kg/dose IV every 8 hours 1
• Postmenstrual age >30 weeks: 80 mg/kg/dose IV every 6 hours 1
• For optimized PMA-based dosing in infants <61 days: 2
  • PMA ≤30 weeks: 100 mg/kg every 8 hours
  • PMA 30-35 weeks: 80 mg/kg every 6 hours
  • PMA 35-49 weeks: 80 mg/kg every 4 hours

Infants 2-6 Months

• Standard dosing: 80 mg/kg every 6 hours infused over 2 hours 3
• For severe infections: 100 mg/kg every 6 hours 1
• Maximum daily dose: 300 mg/kg/day 1

Children >6 Months to 12 Years

• Standard dosing: 240-300 mg/kg/day divided every 6-8 hours 1
• Practical regimen: 90 mg/kg every 8 hours infused over 4 hours 3
• For critically ill children or severe infections: 100 mg/kg every 6 hours as a 3-hour infusion 4
• Alternative for ICU patients: Loading dose of 75 mg/kg followed by continuous infusion of 300 mg/kg/24 hours 5
• Maximum daily dose: 24,000 mg/day (24 grams) 1

Adolescents ≥13 Years

• Use adult dosing: 3.375 g IV every 6 hours 1

Optimized Dosing for Specific Clinical Scenarios

Complicated Intra-Abdominal Infections

• 200-300 mg/kg/day divided every 6-8 hours 1
• Maximize β-lactam dosing (use 300 mg/kg/day) if undrained abscesses are present 1

Critically Ill Children in ICU

• Preferred regimen: 100 mg/kg every 6 hours as a 3-hour prolonged infusion 4
• Alternative: 75 mg/kg every 4 hours over 2 hours 5
• Continuous infusion option: 75 mg/kg loading dose, then 300 mg/kg/24 hours 5
• These extended infusion strategies achieve optimal pharmacodynamic targets (≥50% fT>MIC) against Pseudomonas aeruginosa with MICs up to 16 mg/L 4, 5

Infections with Elevated MIC Organisms

• For organisms with MIC up to 16 mg/L, use 130 mg/kg/dose every 8 hours infused over 4 hours in children >6 months 3
• Standard intermittent dosing (75-80 mg/kg every 6-8 hours) may be insufficient for organisms with MIC ≥16 mg/L 5

Administration Guidelines

Infusion Duration

• Standard infusions: 30 minutes 1
• Extended infusions (preferred for severe infections): 2-4 hours 3, 4, 5
• Extended infusions optimize time above MIC and improve outcomes in critically ill children 5

Renal Function Adjustments

• All dosing recommendations assume normal renal and hepatic function 1
• Doses should be based on total body weight 1
• Monitor renal function during therapy 1

Key Clinical Considerations

When to Maximize Dosing

• Use 300 mg/kg/day (upper end of range) for: 1, 4, 5
  • Undrained intra-abdominal abscesses
  • Critically ill patients in ICU
  • Suspected or documented Pseudomonas aeruginosa
  • Organisms with MIC 8-16 mg/L
  • Severe sepsis or septic shock

Combination Therapy

• For complicated intra-abdominal infections in children, piperacillin-tazobactam is an acceptable broad-spectrum regimen as monotherapy or combined with aminoglycosides 1
• For severe β-lactam allergies, use ciprofloxacin plus metronidazole or aminoglycoside-based regimens instead 1

Common Pitfalls to Avoid

• Underdosing critically ill children: Standard 80 mg/kg every 8 hours may be inadequate for ICU patients; use 100 mg/kg every 6 hours or continuous infusion 4, 5
• Short infusion times in severe infections: 30-minute infusions do not optimize pharmacodynamics; use 3-4 hour infusions for critically ill patients 3, 4, 5
• Ignoring MIC values: For organisms with MIC >8 mg/L, standard dosing achieves suboptimal target attainment; increase dose and extend infusion 4, 5
• Forgetting to adjust for postmenstrual age in neonates: Clearance varies significantly with PMA; use PMA-based dosing for infants <2 months 2
• Not maximizing doses when abscesses are undrained: β-lactam penetration into abscesses is poor; use 300 mg/kg/day until source control achieved 1