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Assessment of acyclovir intraindividual pharmacokinetic variability during continuous hemofiltration, continuous
N Bleyzac1, P Barou, B Massenavette
1Department of Pharmacy, Debrousse Hospital, Lyon, France.
Insights
Intravenous acyclovir dosing in pediatric patients with renal impairment is complex due to pharmacokinetic variability. This study highlights wide variability during renal replacement therapy, with higher elimination during continuous venovenous hemodialysis (CVVHD).
Area of Science:
- Pharmacokinetics and Drug Metabolism
- Pediatric Nephrology
- Critical Care Medicine
Background:
- Intravenous acyclovir dosing in pediatric patients with renal impairment presents challenges due to significant intraindividual pharmacokinetic variability.
- This variability is influenced by the patient's clinical status and evolving renal function.
Observation:
- Therapeutic drug monitoring data and Bayesian adaptive control were used to assess acyclovir pharmacokinetics in a pediatric bone marrow transplant patient with severe renal impairment.
- Acyclovir pharmacokinetic parameters were evaluated during continuous venovenous hemofiltration (CAVH), CAVH with dialysis (CAVHDF), and continuous venovenous hemodialysis (CVVHD).
Findings:
- A wide range of intraindividual pharmacokinetic variability for acyclovir was observed across different renal replacement therapy techniques (CAVH, CAVHDF, CVVHD).
- The acyclovir elimination rate constant was notably higher during CVVHD compared to CAVH or CAVHDF.
- The performance and utility of each dialysis technique influenced the observed variability.
Implications:
- Bayesian methods are valuable for assessing intraindividual pharmacokinetic variability, especially with sparse patient data.
- These findings underscore the need for individualized acyclovir dosing strategies in critically ill pediatric patients undergoing renal replacement therapy.
- Optimizing acyclovir therapy requires careful consideration of the specific renal replacement modality used.
Abstract:
The use of intravenous acyclovir can be particularly complicated in pediatric patients with evolving renal impairment, because of intraindividual pharmacokinetic variability linked to the patient's clinical condition. The objective of this study was to use therapeutic drug monitoring data to assess acyclovir intraindividual pharmacokinetic variability during several types of renal replacement therapy. Bayesian adaptive control of acyclovir dosage regimen was performed in a pediatric patient with bone marrow transplant who developed severe renal impairment. Acyclovir pharmacokinetic parameter values corresponding to the different techniques and periods of renal replacement therapy were estimated using USCPACK PC Clinical Programs and therapeutic drug monitoring data. Results showed a wide intraindividual pharmacokinetic variability during CAVH, CAVHDF, and CVVHD, reflecting not only the performance of each dialysis technique but also the difficulty in making use of each one. The acyclovir elimination rate constant was higher during CVVHD compared to CAVH or CAVHDF. Bayesian method appears to be valuable in assessing intraindividual pharmacokinetic variability, as it allows the clinician to deal with sparse routine patient data.