Is Ceftazidime Dialyzable?
Yes, ceftazidime is significantly removed by hemodialysis, with approximately 50-55% of the administered dose cleared during a typical 4-hour dialysis session. 1, 2
Extent of Dialytic Removal
Hemodialysis removes more than half of circulating ceftazidime, reducing plasma concentrations by approximately 88% during a 6-8 hour session and by roughly 69% (from 64.3 to 20.0 mcg/mL) during a 4-hour session. 2, 3
The elimination half-life drops dramatically during dialysis, decreasing from 33.6 hours in anuric patients between dialysis sessions to only 2.8-3.3 hours during active hemodialysis. 2, 3
Dialyzer clearance of ceftazidime is approximately 55.6 mL/min, with 55% of the administered dose recovered in dialysate fluid after a single hemodialysis session. 2
Mechanism of Dialytic Clearance
Ceftazidime is eliminated by glomerular filtration with minimal protein binding (<10%), making it highly susceptible to removal by hemodialysis since the drug is not actively secreted by renal tubules and probenecid does not affect its elimination. 1
The drug's pharmacokinetic properties favor dialytic removal: low molecular weight, minimal protein binding, and lack of hepatic metabolism result in 80-90% renal excretion of unchanged drug in patients with normal kidney function. 1, 4
Recommended Dosing Strategy for Hemodialysis Patients
Administer 1 g IV ceftazidime immediately after each hemodialysis session for patients on a typical thrice-weekly schedule, as this timing prevents premature drug removal and ensures adequate exposure. 5, 6
Give the dose after dialysis, never before, to avoid significant drug loss during the dialysis session and to facilitate directly observed therapy. 5
A supplemental dose equal to half the usual maintenance dose should be given immediately after each dialysis session to compensate for dialytic losses. 2
Critical Dosing Pitfall to Avoid
Do not reduce the individual dose size; instead, extend the dosing interval to preserve ceftazidime's concentration-dependent bactericidal activity, as smaller doses may reduce drug efficacy. 5
Avoid administering ceftazidime before dialysis, as approximately 40% of the dose is removed when given just before hemodialysis, resulting in subtherapeutic plasma concentrations. 7
Special Considerations
Peritoneal dialysis also removes ceftazidime, though less efficiently than hemodialysis, and may aid in drug removal in cases of overdosage. 1, 4
Continuous renal replacement therapies (CRRT) extensively remove ceftazidime, with extraction coefficients around 1.0 and clearances ranging from 15-35 mL/min depending on the modality and flow rates used. 8
In critically ill patients or those with resistant organisms on CVVH, consider 1.25 g q8h dosing, while those on intermittent hemodialysis may require 1.25 g q24h post-dialysis. 9