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Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
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Age and CYP3A5 genotype affect tacrolimus dosing requirements after transplant in pediatric heart recipients

Violette Gijsen1, Seema Mital, Ron H van Schaik

  • 1Intensive Care and Department of Pediatric Surgery, Erasmus MC Sophia Children's Hospital, Rotterdam, the Netherlands.

The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation
|September 21, 2011
PubMed

Insights

Younger children and those with CYP3A5 expressor genotype require higher tacrolimus doses and have lower drug concentrations after heart transplant. These factors influence dosing and drug levels in pediatric transplant recipients.

Area of Science:

  • Pharmacogenomics
  • Immunosuppression Therapy
  • Pediatric Transplantation

Background:

  • Tacrolimus is a key immunosuppressant in pediatric heart transplants, but significant pharmacokinetic variability poses risks.
  • Limited understanding exists regarding how age, CYP3A5 and ABCB1 genetic variations, and disease severity impact tacrolimus disposition and outcomes in these young patients.

Purpose of the Study:

  • To investigate the influence of age, CYP3A5, and ABCB1 genotypes on tacrolimus dosing, concentration, and clinical outcomes in pediatric heart transplant recipients.
  • To identify key factors affecting tacrolimus pharmacokinetics and inform personalized dosing strategies.

Main Methods:

  • A cohort of pediatric heart transplant recipients (n=39) was analyzed.
  • The study examined correlations between age, CYP3A5/ABCB1 genotypes, and tacrolimus dose, steady-state trough concentrations, concentration/dose ratio, rejection rates, and renal function within 14 days post-transplant.

Main Results:

  • Younger age correlated with increased tacrolimus dosing requirements and higher concentration/dose ratios.
  • CYP3A5 expressors needed higher tacrolimus doses and exhibited lower concentration/dose ratios compared to non-expressors.
  • Neither age nor CYP3A5/ABCB1 genotype showed a relationship with estimated glomerular filtration rate.
  • Age and CYP3A5 genotype were significant predictors of tacrolimus dosing and concentration/dose ratio.

Conclusions:

  • Younger age and CYP3A5 expressor genotype are independent predictors of higher tacrolimus dosing needs and lower tacrolimus concentration/dose ratios in pediatric heart transplant recipients.
  • These findings highlight the importance of pharmacogenetic considerations for optimizing tacrolimus therapy in this population.
Abstract

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