Polymorphic acetylation of sulphamethazine in a Zimbabwe population.

Sulphamethazine, 8 mg/kg body weight, was administered orally in tablet form to 100 healthy volunteers and total and free sulphamethazine were determined in the six hour urine sample. The bimodal population frequency distribution for percentage acetylated sulphamethazine showed 42 of the tested population to be fast and 58 to be slow acetylators, that is, an estimation of q = 0.72 +/- 0.3 as the frequency of the allele controlling slow acetylation. The study also revealed ample evidence that the assay of the drug in urine can be done in a significantly shorter time.