Metabolism of quinine in children with global malnutrition.

Malnutrition and malaria are two important public health problems in Africa. Quinine is one of the major treatments of chloroquine-resistant malaria. Although some authors have shown that quinine clearance is decreased in kwashiorkor, this type of malnutrition is caused by protein deficiency that differs from global protein-energy malnutrition. In rats, hepatic metabolism of many drugs is decreased in protein deficiency and increased in global food restriction. Several studies have found that human hepatic metabolism of many drugs is decreased in kwashiorkor, but, as yet, no study has focused on human global energy-protein malnutrition. Thus, as quinine is a drug with a narrow therapeutic index, we compared the pharmacokinetics of quinine in two groups. One group included children with global malnutrition and the other was a control group of children with normal nutrition. Volume of distribution and plasma concentrations of unbound quinine did not differ between children with global malnutrition and children with normal nutritional status. Clearance was significantly faster, half-life shorter, and concentrations, 12 h after the beginning of treatment, lower in malnourished children compared with control subjects. The ratio between area under the curve of hydroxyquinine (metabolite of quinine in man) and area under the curve of quinine was significantly increased in malnourished children and correlated with mid-arm/ head circumference ratio (marker of malnutrition in children). Thus, as metabolism of quinine is increased in children with global malnutrition, we suggest that the administration interval should be reduced in these children to obtain the same plasma concentrations of quinine found in normally nourished children. A safe and effective dosing strategy is postulated.