Efficacy, Safety, and Practicality of Tacrolimus Monitoring after Bone Marrow Transplant: Assessment of a Change in Practice

Pharmacy residents have the opportunity to complete a research project during their residency training, which provides them with skills on how to conduct and manage a research project. Projects often represent an area of interest and need that has been recognized by the host institution’s pharmacy department. Projects are presented as a poster at an annual CSHP Ontario Branch Residency Research Night, and many eventually go on to be published in a peer-reviewed journal.Background: Currently, there is no standardized approach to the frequency of monitoring tacrolimus levels in patients who have undergone hematopoietic stem cell transplant (HSCT). Previously, the practice at the study hospital was to monitor tacrolimus levels daily throughout a patient’s admission. A recent institutional study suggested that measurement of tacrolimus level is more frequent than needed to achieve consistent time in the therapeutic range (TTR), particularly after the first 7 days. As a result, tacrolimus monitoring was changed to daily measurement for the initial week of therapy, followed by measurements on Monday, Wednesday, and Friday in subsequent weeks. Objective:To confirm the safety and efficacy of the recent practice change. Methods: This retrospective chart review of HSCT patients admitted to The Ottawa Hospital involved 68 patients in the pre–practice change group and 43 patients in the post–practice change group. Data on tacrolimus measurement were collected for up to 21 days after initiation of this medication. The proportion of TTR was compared between the 2 groups. Differences in the incidence and severity of renal dysfunction and the incidence of acute graft versus host disease (GVHD) were determined and described. Results: In the pre–practice change cohort, the median proportion of TTR for tacrolimus was 40.5% for days 1–7, 65.1% for days 8–14, and 78.9% for days 15–21, similar to the values for the post–practice change group (46.6% [p = 0.09], 62.9% [p = 0.93], and 70.0% [p = 0.22], respectively, for the same periods). The incidence of acute GVHD within 100 days after HSCT was 24% and 33% for the pre– and post–practice change cohorts, respectively. The incidence and severity of renal dysfunction were similar between the 2 groups. Conclusion:The proportion of TTR for tacrolimus was not significantly affected by the recent practice change. Similarly, the incidence and severity of renal dysfunction and the incidence of acute GVHD did not appear to differ between the pre– and post–practice change groups