Zavicefta Dosing for a 15-Year-Old Weighing 42 kg
For a 15-year-old patient weighing 42 kg, the recommended dose of Zavicefta (ceftazidime-avibactam) is 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) administered intravenously every 8 hours over 2 hours, assuming normal renal function. 1
Dosing Rationale
Pediatric patients weighing 40 kg or more should receive the standard adult dose of Zavicefta 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) every 8 hours by 2-hour IV infusion 1
At 42 kg body weight, this 15-year-old patient exceeds the 40 kg threshold where adult dosing becomes appropriate, eliminating the need for weight-based pediatric calculations 1
For pediatric patients aged 2 years to less than 18 years with normal renal function (eGFR >50 mL/min/1.73 m²), the maximum dose is capped at 2.5 grams (ceftazidime 2 grams and avibactam 0.5 grams) every 8 hours 1
Administration Details
Infusion time must be 2 hours for all Zavicefta doses to ensure appropriate pharmacokinetic exposure 1
The dosing interval of every 8 hours should be maintained consistently throughout the treatment course 1
For complicated intra-abdominal infections, metronidazole should be administered concurrently at 10 mg/kg IV every 8 hours (maximum 500 mg/dose) 1
Treatment Duration by Indication
- Complicated intra-abdominal infections: 5 to 14 days 1
- Complicated urinary tract infections including pyelonephritis: 7 to 14 days 1
- Hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia: 7 to 14 days 1
Renal Function Considerations
This dosing assumes normal renal function (eGFR >50 mL/min/1.73 m²) 1
If this patient has renal impairment with eGFR ≤50 mL/min/1.73 m², dose adjustments are required using the Schwartz bedside formula to calculate eGFR 1
For eGFR 31-50 mL/min/1.73 m², the dose would be reduced to 1.25 grams (ceftazidime 1 gram and avibactam 0.25 grams) every 8 hours 1
Important Clinical Caveats
Both ceftazidime and avibactam are primarily renally cleared, making renal function assessment critical before initiating therapy 2, 3
The 4:1 fixed-dose ratio of ceftazidime to avibactam is maintained across all dosing regimens due to their complementary pharmacokinetic profiles with similar half-lives of approximately 2 hours 3
This dosing regimen achieves the pharmacodynamic targets of 50% fT>MIC for ceftazidime and 50% fT>1 mg/L for avibactam, which have been validated in phase III trials 3, 4