Intraperitoneal Antibiotic Dosing for Pediatric Peritoneal Dialysis Peritonitis
For pediatric PD peritonitis, administer intraperitoneal ceftazidime at 125 mg/L in each dialysate exchange and gentamicin at 0.6 mg/kg body weight per exchange (loading dose 8 mg/L, maintenance 4 mg/L), based on established pediatric dosing protocols that achieve therapeutic serum and dialysate concentrations. 1
Ceftazidime Dosing
- Continuous maintenance dosing of 125 mg/L in each dialysate bag achieves therapeutic levels without requiring a loading dose 1
- This concentration produces serum levels of approximately 29 mcg/mL after short cycles and 24 mcg/mL at 24 hours, with dialysate concentrations of 87 mcg/mL and 32 mcg/mL respectively 1
- Therapeutic concentrations exceeding the mean inhibitory concentration (MIC) for sensitive organisms are achieved within 4 hours and persist for 24 hours 1
- Serum bioavailability reaches 74% at 24 hours with this regimen 1
Gentamicin Dosing
- Administer 0.6 mg/kg body weight per exchange for pediatric patients (based on extrapolation from adult dosing adjusted for pediatric pharmacokinetics) 2
- Alternative approach: Loading dose of 8 mg/L in one exchange, followed by maintenance dose of 4 mg/L in subsequent exchanges 3
- Once-daily dosing at 40 mg per 2L in the overnight/long-dwell bag is effective and reduces toxicity risk 4, 5
- Monitor serum gentamicin levels and renal function, targeting trough levels <2 mcg/mL to minimize ototoxicity and nephrotoxicity 2
Critical Dosing Considerations
- Weight-based dosing for gentamicin (3-7.5 mg/kg/day) should be calculated on total body weight 2
- For continuous cycling peritoneal dialysis (CCPD) patients, the continuous maintenance approach without loading dose is validated and effective 1
- Once-daily gentamicin administration achieves treatment success rates of 74-80% for gram-negative organisms (excluding pseudomonas) 4
- Antibiotic serum concentrations and renal function must be monitored throughout therapy 2
Treatment Duration and Monitoring
- Continue therapy until dialysate clears (typically 14-21 days for most organisms) 1, 3
- Adjust antibiotics based on culture results when available 3, 6
- Treatment success rates with ceftazidime-gentamicin combinations range from 75-80% 3, 6
- Relapse rates are approximately 9-18% within 4 weeks of completing therapy 3, 5
Important Caveats
- These doses assume normal residual renal function; adjust for anuric patients or those with significant residual function 2
- For Pseudomonas peritonitis, higher ceftazidime doses or alternative agents may be required 4
- The once-daily gentamicin approach produces lower trough levels (0.75 mg/L vs 1.5 mg/L with multiple dosing), potentially reducing toxicity while maintaining efficacy 5
- Vancomycin (15-30 mg/kg loading dose, then 1-2 g per week maintenance) should be added for gram-positive coverage until cultures exclude these organisms 3, 6