[Clinical significance of genetically determined polymodality of the distribution of quinidine elimination rates].

A population study of quinidine half-elimination time distribution has demonstrated a trimodality of distribution that is due to different rates of metabolic quinidine oxidation. The ratio of permanent serum concentrations of 3-oxyquinidine (metabolite) to quinidine in the rapid oxidation group was elevated significantly, as compared to slow oxidation groups. The values obtained in these phenotypic groups show good correspondence to the Hardy-Weinberg law, with a 0.755 frequency of the allele controlling high monooxygenase activity, and a 0.244 frequency of the gene for the low activity. Effective daily doses should be 1.5-2 times as high in high oxidants (57% of the population) as they are in slow oxidants (37%), and 2.5-3 times as high, as compared to very slow oxidants (6%).