Ceftazidime Renal Dose Adjustment
In adults with renal impairment, reduce ceftazidime dosing frequency based on creatinine clearance: give 1 gram every 12 hours for CrCl 31-50 mL/min, every 24 hours for CrCl 16-30 mL/min, 500 mg every 24 hours for CrCl 6-15 mL/min, and 500 mg every 48 hours for CrCl <5 mL/min. 1
Standard Dosing in Normal Renal Function
- The usual adult dose is 1 gram IV or IM every 8-12 hours for most infections 1
- For severe life-threatening infections or immunocompromised patients, increase to 2 grams IV every 8 hours 1
- Cystic fibrosis patients with normal renal function require 30-50 mg/kg IV every 8 hours (maximum 6 grams/day) due to increased volume of distribution and enhanced renal clearance 1
Renal Dose Adjustment Algorithm
Initial Loading Dose: Give 1 gram of ceftazidime as a loading dose in all patients with suspected renal insufficiency before adjusting maintenance dosing 1
Maintenance Dosing by Creatinine Clearance:
- CrCl 50-31 mL/min: 1 gram every 12 hours 1
- CrCl 30-16 mL/min: 1 gram every 24 hours 1
- CrCl 15-6 mL/min: 500 mg every 24 hours 1
- CrCl <5 mL/min: 500 mg every 48 hours 1
Important Caveat:
If the standard dose for the infection type (from Table 3 in the label) is lower than the renal-adjusted dose, use the lower dose 1. For example, uncomplicated UTI requires only 250 mg every 12 hours even with normal renal function, so don't increase this in mild renal impairment.
Pharmacokinetic Rationale
- Ceftazidime is almost exclusively eliminated by glomerular filtration with minimal protein binding and no metabolism 1, 2
- The elimination half-life increases from 1.5-2 hours in normal function to 36-48 hours in severe renal failure 2, 3
- Ceftazidime clearance correlates directly with creatinine clearance, ranging from 7.5 to 145.1 mL/min depending on renal function 3
Dialysis Considerations
Hemodialysis:
- Give a 1 gram loading dose initially 1
- Follow with 1 gram after each hemodialysis session 1
- The mean half-life during hemodialysis is approximately 4.7 hours, indicating significant drug removal 4
Peritoneal Dialysis:
- Give a 1 gram loading dose 1
- Maintenance: 500 mg every 24 hours 1
- Alternatively, incorporate 250 mg per 2 liters of dialysis fluid for intraperitoneal administration 1
- For chronic peritoneal dialysis, use 10 mg/kg loading dose followed by 5 mg/kg into each dialysis cavity 2
Severe Infections in Renal Impairment
For patients with severe infections who would normally receive 6 grams daily but have renal insufficiency, increase the unit dose by 50% or increase dosing frequency appropriately 1. This maintains adequate exposure for serious infections while accounting for reduced clearance.
Critical Pitfalls to Avoid
- Don't skip the loading dose: Always give 1 gram initially in renal impairment to achieve therapeutic levels quickly 1
- Don't reduce individual doses too aggressively: Extend the interval rather than reducing the dose below 500 mg, as smaller doses may compromise efficacy 3
- Don't forget post-dialysis dosing: Hemodialysis removes significant amounts of ceftazidime, requiring supplemental dosing after each session 1, 4
- Monitor for accumulation: In severe renal failure (CrCl <15 mL/min), the half-life can extend to 45 hours, requiring careful interval extension 4
Estimating Creatinine Clearance
When only serum creatinine is available, use the Cockcroft-Gault equation 1:
- Males: CrCl (mL/min) = [Weight (kg) × (140 - age)] / [72 × serum creatinine (mg/dL)]
- Females: 0.85 × male value
The serum creatinine must represent steady-state renal function for accurate estimation 1.