Quinine levels in patients with uncomplicated falciparum malaria in the Amazon region of Brazil

Abstract

We examined the plasmatic concentrations of quinine in patients with uncomplicated falciparum malaria in an endemic area of the Amazon region in Brazil in a prospective clinical trial, in which a standard three-day course of oral quinine plus doxycycline was used. We measured the quinine in the plasma samples on days 0 and 3by high performance liquid chromatography. The mean concentration of quinine was 6.04 ±2.21 μ μ μ μ μg/mL in male patients and 5.98 ±1.95 μ μ μ μ μg/mL in female patients. No significant differences in quinine concentration were observed between these two groups. All samples collected before starting treatment were negative for quinine. This information could help in the development of strategies for the rational use of antimalarial drugs in Brazil.

Recurrence of Plasmodium falciparum after treatment with quinine and doxycycline in the Amazon basin

“…Plasma quinine concentrations in both groups are in agreement with reports of adult male patients from the same endemic areas and from other countries . These data also confirm an adequate exposure to the drug, which is a determinant of its therapeutic efficacy.…”

Effect of dehusked Garcinia kola seeds on the overall pharmacokinetics of quinine in healthy Nigerian volunteers

“…The precise therapeutic window, however, remains uncertain as various factors have been reported to affect the pharmacokinetic and therapeutic responses of quinine. 34,35 In these studies, the pharmacokinetic parameters of a single dose administration of quinine were in concordance with values reported in the literature. 36,37 Interestingly, we observed that during drug administration and blood sample collection, the incidences of adverse reactions to quinine were significantly reduced when G. kola was co-administered with quinine.…”

“…The precise therapeutic window, however, remains uncertain as various factors have been reported to affect the pharmacokinetic and therapeutic responses of quinine . In these studies, the pharmacokinetic parameters of a single dose administration of quinine were in concordance with values reported in the literature .…”

“…Indeed, the reduction in C max and AUC 0–∞ of quinine and its metabolite after concomitant intake of quinine with G. kola as observed in the current studies suggest a possible reduction in toxic effects or adverse effects of quinine. This observation is in agreement with the previous report where higher plasma concentrations of quinine are associated with manifestations of toxic effects …”

“…This observation is in agreement with the previous report where higher plasma concentrations of quinine are associated with manifestations of toxic effects. 35 There are several reports of other commonly consumed supplements with significant effects on drug bioavailability and disposition. For example, kola nut has been reported to cause a significant decrease in the plasma concentration of halofantrine and its metabolite when coadministered 28 and Tamarindus indica the major component of a local drink widely taken in the Northern part of Nigeria has been reported to significantly decrease the bioavailability of aspirin in healthy human subjects.…”