Red Cell Quinine Concentrations in Falciparum Malaria

Red cell concentrations of quinine were measured in cerebral malaria and in uncomplicated falciparum malaria both in the acute stage and 1 month after recovery. Red cell quinine elimination half times were significantly shorter than the corresponding plasma half times in cerebral malaria and convalescent uncomplicated cases (P < 0.001), but not in acute uncomplicated cases (P = 0.12). The ratio of red cell:plasma concentration fell progressively from the 2nd day (0.49) to the 6th day (0.26) of treatment. On admission this ratio was positively correlated with the blood parasite count (P = 0.02). Red cell quinine concentration may be relevant to the assessment of drug resistance, and to the design of treatment regimens.