Determination of initial i.v. CYA dosage to achieve target AUC values in pediatric hematopoietic stem cell transplant patients.

In solid organ transplantation, CYA dosing is based on the area under the concentration vs time curve (AUC(inf)). This study aimed to develop a guideline for the initial i.v. CYA dose for pediatric hematopoietic SCT (HSCT) patients to achieve the target AUC(inf) recommended in solid organ transplantation. Whole-blood CYA concentrations were determined in 24 patients (0.5-16.9 years) after the first i.v. dose given over 2 h, 1 day before HSCT. The i.v. CYA dose predicted to achieve an AUC(inf) of 4200 microg x h/l was calculated for each patient and expressed as a function of each patient's actual weight and body surface area (BSA). In patients <or=9 and >9 years of age, the mean i.v. CYA dose predicted to achieve the target AUC was 2.6+/-0.94 and 2.1+/-1.21 mg/kg, respectively. When these doses were expressed in terms of BSA, the mean dose was 65+/-23.1 and 68+/-35.0 mg/m(2) in children <or=9 and >9 years of age, respectively. In children 0.5-17 years of age undergoing HSCT, we recommend an initial i.v. CYA dose of 65 mg/m(2) infused over 2 h to achieve an AUC(inf) of approximately 4200 microg x h/l.