What is the recommended dosing of Zosyn (piperacillin/tazobactam) in patients with impaired renal function undergoing dialysis?

Dosing of Zosyn in Dialysis Patients

For hemodialysis patients, administer piperacillin/tazobactam 2.25 g every 12 hours for most infections (or every 8 hours for nosocomial pneumonia), with an additional 0.75 g dose given after each dialysis session. 1

Hemodialysis Dosing Recommendations

The FDA-approved dosing for piperacillin/tazobactam in hemodialysis patients is based on the degree of renal impairment and indication 1:

For All Indications Except Nosocomial Pneumonia:

• 2.25 g every 12 hours 1
• Supplemental dose: 0.75 g (0.67 g piperacillin/0.08 g tazobactam) after each hemodialysis session 1

For Nosocomial Pneumonia:

• 2.25 g every 8 hours 1
• Supplemental dose: 0.75 g after each hemodialysis session 1

Key Principles for Dialysis Dosing

Hemodialysis removes 30-40% of the administered piperacillin/tazobactam dose, necessitating post-dialysis supplementation 1. The rationale for this approach:

• Piperacillin is partially cleared by hemodialysis, though less efficiently than smaller molecules 2
• The extended dosing interval (every 12 hours vs. every 6 hours in normal renal function) accounts for reduced renal clearance 1
• Post-dialysis dosing prevents premature drug removal and ensures adequate serum concentrations 3

CAPD (Continuous Ambulatory Peritoneal Dialysis) Dosing

For patients on CAPD 1:

• 2.25 g every 12 hours for most infections
• 2.25 g every 8 hours for nosocomial pneumonia
• No additional supplemental doses are required (unlike hemodialysis) 1

Intraperitoneal Administration for CAPD Peritonitis:

If treating peritonitis with intraperitoneal administration 4, 5:

• Loading dose: 4 g/0.5 g (piperacillin/tazobactam) intraperitoneally
• Maintenance: 1 g piperacillin every 6 hours in dialysate 5
• Note that intraperitoneal absorption increases with peritoneal inflammation and normalizes as infection resolves 5

Administration Timing

Always administer piperacillin/tazobactam after hemodialysis on dialysis days 1, 3. This approach:

• Prevents drug loss during the dialysis session
• Maintains therapeutic concentrations throughout the interdialytic period
• Simplifies directly observed therapy when applicable

Important Caveats

• The standard 30-minute intravenous infusion time should be maintained even in dialysis patients 1
• Pediatric dosing in renal impairment has not been established; use adult dosing for pediatric patients >40 kg with renal failure 1
• These recommendations apply specifically to intermittent hemodialysis; data for other dialysis modalities (e.g., continuous renal replacement therapy) require different dosing strategies not addressed in the FDA label 1