Clinically significant drug interactions of Eltrombopag: a retrospective study from the clinical pharmacist perspective

Introduction: Thrombopoietin is the main cytokine regulating megakaryopoiesis and platelet production. Eltrombopag interacts with the transmembrane domain of thrombopoietin receptors and initiates signaling cascades inducing proliferation and differentiation from bone marrow progenitor cells. The aim of the study was to determine drug interaction at patients that are receiving Eltrombopag along with other medications. Materials and methods: A retrospective, longitudinal study was conducted at the Hematology Clinic in Skopje, N. Macedonia. A clinical pharmacist, focusing on Eltrombopag and concomitant medications interactions, reviewed a total number of 16 patient’s histories for the period of 6 months (January-June 2023). Anamnestic data on additional drugs, herbal supplements, vitamins, minerals were also taken. Potential drug interactions were identified using Stockley's interactions checker, categorized by severity and subclassified into co-administered drugs altering pharmacokinetics. Results: A total number of 73 interactions were identified, of which 23 (31.51%) were with moderate clinical relevance, 14 (19.18%) were with no clinical importance and required counseling about possible adverse effects and additional monitoring. The rest of 36 (49,32%) interactions were without clinical significance. Additionally, we determine that 7 (9.59%) of total interactions directly related to patients receiving Eltrombopag (ciclosporin, atorvastatin, rosuvastatin, dexamethasone, prednisolone, valsartan, and magnesium) and categorized as moderate and needs close monitoring. Conclusion: This study demonstrates toxicity potential of Eltrombopag at patients associated with concomitant medicines. Close collaboration of physicians and clinical pharmacists is necessary in all cases where patients are receiving Eltrombopag along with other medications in order all significant interactions to be identified, prevented and managed

Determination of non-adherence in patients receiving Eltrombopag

Eltrombopag, an orally administered thrombopoietin receptor agonist, selectively binds to the transmembrane domain of the thrombopoietin receptor on the surface of platelets, megakaryocytes and megakaryocyte precursor cells (1). The aim of our research is to determine patient non-adherence and its impact on the effectiveness and safety of prescribed therapy, as well as the possibility of treatment failure. The observational, longitudinal, and retrospective study was conducted in the PHO University Clinic of Hematology in Skopje, R.N.Macedonia. 17 patients (9 men and 8 women) were followed from January to August 2023. Five of them were with diagnose aplastic anemia and 12 with immune thrombocytopenia. All of them treated with Eltrombopag. We have systematically reviewed medical records from the Department of Hospital pharmacy, collected anamnestic data and determine non-adherence to therapy, followed by dose frequency, double taking therapy, omitted doses, drug-drug interactions and food/supplement-drug interactions. Thirteen types of non-adherence were identified, of which 3(23,08%) were related to dose frequency, 1(7,69 %) was related to double taking therapy, 5(38,46%) were related to the possibility of drug-drug interactions, 2(15,38%) with possibility for food/supplement-drug interactions and 2(15,38 %) were related with omitted doses. Failure to adherence is a serious problem which not only affects the patient but also the health care system. The clinical pharmacist intervention can improve patient adherencе, because the most important determinants effectiveness and safety are adherence to the prescribed therapy, multiple drug and food/supplement interactions which can vary on dose-response relationship, and risk of insufficient effectiveness of therapy (2)