Excretion patterns of alkylating metabolites in urine following cyclophosphamide treatment of tumor patients: influence of application route, dosage, liver and kidney function.

The excretion patterns of cyclophosphamide (CP) in urine were studied in 54 tumor patients aged between 21 and 61 years, using the nitrobenzyl-pyridine (NBP) reaction, with regard to the route of application (i.v., i.m. or oral), the CP dose and the functional state of the liver and kidney. The studies were carried out in nephrectomized patients and patients with liver affections caused by the basic disease, in particular with malignant lymphomas and mammary carcinomas. The following results were obtained: 1. There exists a direct relationship between the dose of CP applied and the quantitative excretion of alkylating metabolites in urine. According to these studies in which the patients received up to 2.8 g CP/m2 body surface, the upper CP dose was limited by the generally toxic side effects rather than by the metabolization rate. 2. At comparable CP doses the route of application (i.v., i.m. or oral) has no appreciable influence on the excreted NBP activity. 3. Disorders of the liver function without signs of icterus are not a contraindication to CP treatment. 4. The functional failure of one kidney has no statistically significant influence on the excretion of alkylating metabolites in urine.