Ifosfamide cardiotoxicity in humans.

Ifosfamide (IFS) is a new alkylating oxazaphosphorine related to cyclophosphamide. Various side effects have been reported; however, cardiotoxicity is not known to occur in humans. We report for first time acute cardiac side effects upon IFS treatment in the form of supraventricular arrhythmias and ST-T wave changes. IFS dose ranged from 6.5 g/m2 to 10 g/m2 fractionated in 3 or 5 days and infused i.v. over 4 h daily together with 2-mercaptoethane sulphonate sodium (Mesna). Arrhythmias appeared to be reversible upon discontinuation of the drug. In one patient, readministration of IFS led to arrhythmia that was refractory to treatment. Factors predisposing to the development of cardiac side effects could not be determined in this study. We suggest that patients who receive IFS treatment should be monitored for the occurrence of cardiac abnormalities. Readministration of the drug may be contraindicated in such patients.