Acetaminophen and Chlorpheniramine Maleate Premedication among Patients with Chronic Transfusion: a Prospective, Randomized Controlled Trial

Introduction: Patients with chronic transfusion, especially those with transfusion-dependent thalassemia, are susceptible to transfusion reactions. Acetaminophen and/or chlorpheniramine maleate (CPM) are commonly used as premedication in Thailand, although their efficacy in preventing transfusion reactions remains unclear. This study aims to evaluate the efficacy of acetaminophen and CPM in preventing febrile nonhemolytic transfusion reaction (FNHTR) and allergic transfusion reaction (ATR) before leukocyte-poor packed red cells (LPRC) transfusion.Methods: This study is a prospective, randomized controlled trial involving patients with chronic transfusionaged 18 years. Patients were randomly assigned to either receive oral acetaminophen and intravenous CPM or placebo (calcium carbonate and normal saline) before LPRC transfusion. The primary endpoint was the combined incidence of FNHTR and ATR amongpatients receiving premedication compared with those receiving placebo. This study was registered at Thai Clinical Trial Registry Study ( TCTR20221011002).Results: Ninety-four patients were recruited, with 46 in the premedication arm and 48 in the placebo arm. The incidence of FNHTR and allergic transfusion reaction in the premedication arm and the placebo arm was 0% and 2.1%, respectively (P = 0.33). FNHTR occurred in one patient in the placebo arm, and no patients presented ATR. No adverse events were reported with any medication.Conclusions: Among patients with chronic transfusion receiving LPRC, the incidence of FNHTR or ATR is low. Premedication with oral acetaminophen and intravenous CPM did not have benefits in preventing transfusion reactions. Therefore, acetaminophen and CPM could be safely omitted in chronic transfused patients without a history of transfusion reactions