Ferrioxamine excretion in iron-loaded man.

D ESFERRIOXAMINE (DF) is currently the most eflective chelator available for the treatment of iron overload in man.’2 Intramuscular injections reduce the rate of iron accumulation and have been shown to arrest the progress of hepatic fibrosis in children with transfusion-dependent thalassemia.3 However, used in this fashion, the drug removes a limited amount of iron, and there has been extensive effort directed at improving its effectiveness. Ascorbic acid administration with the chelator has been shown to increase urinary iron loss in iron-loaded subjects.4’5 Continuous infusions are superior to intermittent injections in the amount of urinary iron excretion they generate and, given subcutaneously, are now widely used in an attempt to prevent ultimately fatal iron loading in thalassemia.’9 Despite the extensive clinical use of DF, information concerning its site of action is conflicting, particularly concerning reticuloendothelial cells versus parenchymal contributions.’#{176} 2 In addition, although early studies suggested that in idiopathic hemochromatosis about one-third of the total iron mobilized by intermittent DF injections was in the feces,’3 a less pronounced fecal iron loss was seen in thalassemia,’4 and there has been no systematic study of iron excretion via this route in response to DF infusions. In the present study, DF infusions were administered to subjects with iron overload, and changes in the distribution of chelate iron between urine and stool were monitored at dif-