In Vitro Analysis of Potential Drug Loss of Tacrolimus and Modified Cyclosporine Via Nasogastric Tube
by Dione Foon
Coauthors: David Choe, PharmD, Pharmacy, Children's Hospital Los Angeles, Los Angeles, CA Dorothy Dokko, MSN, CPNP-AC, Bone marrow transplant, Children's Hospital Los Angeles, Los Angeles, CA Yi Xiao, Ph.D., DABCC, CLS, Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, CA Edward Leung, PhD, DABCC, FAACC, Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, CA Teresa Rushing, PharmD, BCPS, BCOP, Pharmacy, Children's Hospital Los Angeles, Los Angeles, CA
Introduction: There is a lack of data regarding administration of immunosuppressive agents such as tacrolimus or modified cyclosporine via nasogastric (NG) tube. The current guidelines recommend avoiding NG administration of these drugs; however that is not always feasible, especially in the pediatric population. Objectives: The purpose of this study is to perform an in vitro analysis measuring drug concentrations before and after simulated administration of tacrolimus or modified cyclosporine via NG tube to determine how much drug loss occurs. Methods: Extemporaneously prepared tacrolimus suspension and commercially available modified cyclosporine solution will be measured before and after passing through common available polyurethane NG tube sizes used in the pediatric population. Analysis of the drug concentration by mass spectrometry will be used to quantify the potential drug loss via the NG tube and results will be reported. Results: The percent change between actual and expected concentration of tacrolimus shows a difference of 2.1% for the 6Fr 56cm tube, 1.2% for the 6Fr 91cm tube, and 1% for the 8Fr 91cm tube. The total range for each tube was (11.8, -3.6%), (8.7%, -12%), and (10.9%, -11.1%), respectively. The range in % change was likely that of measurement error as there were times that the actual concentration was higher than the expected concentration, even with the first flush for the respective tube. It was determined that a margin of error of 10% is acceptable and applicable for clinical practice. See attached box plot figure. Conclusion: Quantifying drug loss of these crucial medications will help guide clinical practice by either: supporting the use of NG administration of these drugs or showing that significant drug loss is observed that may drive a practice change to either promote avoidance of route of administration or quantify drug loss for proactive dose modifications when initiating NG administration of these drugs. This study can confidently support the NG administration of tacrolimus without drug loss and without need for any modifications to current clinical practice to facilitate its administration.