A prospective, randomized, double-blind controlled trial of acetaminophen and diphenhydramine pretransfusion medication versus placebo for the prevention of transfusion reactions.

BACKGROUND: Acetaminophen and diphenhydramine are commonly used as pretransfusion medications to prevent transfusion reactions. The purpose of this study was to prospectively compare the risk of transfusion reactions in hematology/oncology patients who receive acetaminophen with diphenhydramine or placebo before transfusion.

STUDY DESIGN AND METHODS: A randomized, double-blind, placebo-controlled transfusion reaction study of 315 eligible patients was performed. Inclusion criteria were patients aged 18 to 65 years admitted to the leukemia or bone marrow transplant (BMT) services. Patients were excluded if they had a known allergy to either acetaminophen or diphenhydramine or had a documented history of a febrile or allergic transfusion reaction. All blood products were administered using a leukofilter. Study medications were given 30 minutes before transfusions and no other acetaminophen or diphenhydramine was given within 4 hours of administration of the study medications. Patients were monitored for the development of reaction symptoms within 4 hours after the transfusion.

RESULTS: A total of 154 active drug patients were compared to 161 placebo patients. There was no significant difference in the overall risk of transfusion reactions between the two groups. However, analysis of specific reaction types revealed a significant decrease in the risk of febrile reactions when pretransfusion medication is used in addition to bedside leukoreduction.

CONCLUSIONS: Pretransfusion medication of leukemia or BMT patients without a history of transfusion reaction does not decrease the overall risk of transfusion reactions. However, pretransfusion medication may decrease the risk of febrile nonhemolytic transfusion reactions to leukoreduced blood products.