Polymorphic acetylation of sulphadimidine in normal and uraemic man.

After oral administration of sulphadimidine (mean dose 3.33 g) to 21 volunteers it was possible to distinguish fast and slow acetylators by calculating the acetylated fraction (%acSDD) in a single serum sample obtained at any time between 1/2-24 h. There was a close correlation between %acSDD in serum and in urine collected from 0-8 h. Two groups of patients with chronic renal failure were studied. Four of the first 8 patients studied would have been designated as slow acetylators from their low %acSDD in 0-8 h urine, but as fast acetylators from their %acSDD in serum 6 h after drug administration. The next 18 patients were given a smaller dose of SDD (2 g) and they showed complete intra-individual correlation between %acSDD in 0-24 h urine and in a serum sample obtained at 24 h. The patients could be divided into 2 sub-groups on the basis of %acSDD in serum and urine, thus demonstrating the ability of this procedure to distinguish fast and slow acetylators, even in advanced chronic renal failure.