Azathioprine metabolism in kidney transplant recipients.
Azathioprine metabolite concentrations were studied in 54 kidney transplant recipients. Thirty-seven of these patients were studied over a 6 month period to investigate the intrapatient variation in metabolite concentrations. All patients had stable functioning grafts and normal peripheral white blood cell counts. The metabolites measured were plasma 6-mercaptopurine and red blood cell 6-thioguanine nucleotide. There was no correlation between azathioprine dose and plasma 6-mercaptopurine concentration but there was a significant correlation between dose and red blood cell 6-thioguanine nucleotide concentration (rs = 0.41, P less than 0.005). The individual transplant recipient showed little variation in metabolite concentrations over several months. Using this group as a control we studied metabolite concentrations in patients with kidney transplants who developed leucopenia. Our preliminary findings indicate that elevated red cell 6-thioguanine nucleotide concentrations, above the control range, can be associated with bone marrow depression.
D000328:Adult; D000493:Allopurinol / Q000494:pharmacology; D001379:Azathioprine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006150:Guanine Nucleotides / Q000097:blood; D006801:Humans; D007206:Individuality; D016030:Kidney Transplantation; D007958:Leukocyte Count; D007970:Leukopenia / Q000139:chemically induced; D008297:Male; D012737:Sex Factors; D013873:Thionucleotides / Q000097:blood
D006150:Guanine Nucleotides; D013873:Thionucleotides; C003964:6-thioguanylic acid; D000493:Allopurinol; D001379:Azathioprine