Journal of Research in Pharmacy Practice

Abstract Objective: Opportunistic infections like cytomegalovirus (CMV) are among the 
primary causes of morbidity and mortality in patients undergoing hematipoetic stem 
cell transplantation (HSCT). This infection is frequently seen in early postengraftment 
period. So we determined to find the risk factors associated with CMV reactivation.
Methods: We retrospectively evaluated the medical records of 126 consecutive patients 
who underwent allogenic‑HSCT from peripheral blood stem cells from August 2011 to 
February 2013 in Shariati Hospital. We included HSCT patients with 15 years of age 
or older, who survived at least 100 days after transplantation. CMV reactivation was 
detected based on the weekly PP65 assessment. Patients with 10 or more positive cells 
per 50,000 cells were defined as having high‑level antigenemia.
Findings: From 126 patients which included in this study, 76 were male (60%). CMV 
antigenemia was documented in 43 patients (34%). The median time to CMV infection 
was 40 days (range: 3–77) after transplantation. The incidence of high‑level antigenemia 
during the first 100 days following HSCT was 11%.
Conclusion: We found that the significant risk factor for CMV antigenemia in multivariate 
analysis was prior graft‑versus‑host disease (GVHD) experience and higher donor age. For 
high‑level antigenemia, GVHD or duration of its treatment was significant determinant.

Abstract Objective: Many hematopoietic stem cell transplantation (HSCT) patients receive 
vancomycin empirically during febrile neutropenia. There are several models for estimation of 
vancomycin pharmacokinetic parameters and calculation of initial dosing regimen accordingly. 
However, the performance of these methods in HSCT patients remained to be evaluated. 
The aim of the study was to determine which of the vancomycin population pharmacokinetic 
methods best fit Iranian HSCT patients.
Methods: In order to evaluate predicted performance of seven vancomycin population 
pharmacokinetic models, the pharmacokinetic parameters of patients were estimated using 
each model’s equations. Then the predicted steady‑state trough vancomycin concentration was 
calculated based on each model’s parameters and using a formula based on Sawchuk–Zaske 
method. The predicted steady‑state trough vancomycin concentration and the real measured 
concentrations were compared to see which method was the most precise and least biased 
using mean squared error (MSE) and mean prediction error (ME) respectively.
Findings: Forty‑six patients (65% men) were included in the study. Calculated metrics showed 
a range of 38% under‑prediction bias with Rodvold to 34% over‑prediction bias with Matzke and 
Burton models. Birt and revised Burton methods showed no significant bias(ME [95% confidence 
interval(CI)]: –0.067 [–0.235–0.101] and 0.066 [–0.105–0.238]). Birt and revised Burton were not 
different significantly considering MSE (95% CI) of 0.385 (0.227–0.544) and 0.401 (0.255–0.546), 
respectively. Comparisons of precision with naive predictors revealed a delta MSE (95% CI) 
of –0.128 (–1.379–1.890) for Birt and 0.026 (–0.596–0.940) for revised Burton models.
Conclusion: Although the Birt and Burton revised methods performed well, none of the 
studied models showed acceptable performance to be implemented as a routine method 
for initial dose calculation in HSCT patients. A vancomycin pharmacokinetic model specific 
for this high‑risk subpopulation of Iranian patients should be designed and validated.