Measurements of prednisolone and some of its metabolites, in urine of patients after orthotopic liver transplantation, as a means of monitoring prednisolone absorption.

In patients who had undergone orthotopic liver transplantation, malabsorption of prednisolone or increased metabolism of prednisolone was suspected. In order to rule out this possibility, urinary prednisolone, and some of its metabolites, viz prednisone and 6 beta-hydroxyprednisolone, were determined by means of a gas chromatographic assay. To evaluate this assay aliquots of a pooled urine from several of our patients were analysed in multiplicate (n = 10). Mean prednisone, prednisolone and 6 beta-hydroxyprednisolone concentrations of 1.9 mg/l, 6.3 mg/l and 4.1 mg/l, respectively, were found with the following respective day-to-day coefficients of variation: 12.3%, 5.2% and 5.3%. Amounts of prednisolone metabolites excreted in the urine of these patients were correlated with the ingested daily dose of prednisolone. It was concluded that overall absorption of prednisolone in these patients was adequate and not influenced by shortage of bile acids in the gastro-intestinal tract, or by steatorrhoea, both caused by external bile drainage. In addition there was no evidence for increased metabolism of prednisolone.