Dexrazoxane reduces antithrombin activity: a case series

UNLABELLED: Dexrazoxane prevents anthracycline-induced cardiotoxicity and treats anthracycline extravasation. Although thrombosis is not a commonly observed adverse effect of dexrazoxane, a potential association has been suggested. We present three patients (four episodes) who experienced decreased antithrombin activity after dexrazoxane administration. All patients were prescribed dexrazoxane to protect soft tissues from anthracycline extravasation during chemotherapy for hematological malignancies. This led to a reduction in antithrombin activity after a median of 4 days from the first dexrazoxane injection. The activity levels recovered several days later, and one patient developed deep-vein thrombosis. There was no apparent explanation other than dexrazoxane use, raising the possibility that dexrazoxane may be associated with decreased antithrombin activity. We hypothesize that this decrease in antithrombin activity may contribute to thrombosis after dexrazoxane injection. Based on these cases and a review of previous reports on dexrazoxane and thrombosis, it is recommended that clinicians monitor antithrombin decline and thrombosis development in patients undergoing dexrazoxane treatment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13691-026-00848-4.