Pharmacokinetic interaction of chloroquine and methylene blue combination against malaria
- 298 Downloads
The combination of chloroquine and methylene blue is potentially effective for the treatment of chloroquine-resistant malaria caused by Plasmodium falciparum. The aim of this study was to investigate whether methylene blue influences the pharmacokinetics of chloroquine.
In a randomized, placebo-controlled, parallel group design, a 3-day course of therapeutic oral doses of chloroquine (total 2.5 g in male, 1.875 g in female participants) with oral co-administration of placebo or 130 mg methylene blue twice daily for 3 days was administered to 24 healthy individuals. Chloroquine, desethylchloroquine, and methylene blue concentrations were determined by means of HPLC/UV or LC/MS/MS assays in whole blood, plasma, and urine for 28 days after the last dose.
During methylene blue exposure, the area under the chloroquine whole blood concentration–time curve normalized to body weight (AUC0-24 h/BW) yielded a trend of reduction (249±98.2 h μg l−1 kg−1 versus 315±65.0 h μg l−1 kg−1, P=0.06). The AUC0-24 h/BW of desethylchloroquine was reduced by 35% (104±40.3 h μg l−1 kg−1 versus 159±66.6 h μg l−1 kg−1, P=0.03), whereas the metabolic ratio between chloroquine and desethylchloroquine remained unchanged (2.25±0.49 versus 1.95±0.42, P=0.17). The renal clearance of chloroquine and the ratio between chloroquine in whole blood and plasma remained unchanged (P>0.1).
Oral co-administration of methylene blue appears to result in a small reduction of chloroquine exposure which is not expected to be clinically relevant and thus represents no concern for further development as an anti-malarial combination.
This study was supported by DSM Fine Chemicals Austria, Linz, Austria. We thank Mrs. Dorothea Schimpf, MS, for preparing the study medication; Mrs. Brigitte Tubach for study support; and Mrs. Andrea Deschlmayr and Mrs. Magdalena Longo for their excellent technical assistance. The study was approved by the ethics committee of the Medical Faculty of the University of Heidelberg, and was conducted at the Department of Internal Medicine VI, Clinical Pharmacology and Pharmacoepidemiology in accordance with the Declaration of Helsinki, as amended in Somerset West 1996, and the specific legal requirements in Germany.
- 3.Trape JF (2001) The public health impact of chloroquine resistance in Africa. Am J Trop Med Hyg 64:12–17Google Scholar
- 7.Guttmann P, Ehrlich P (1891) Über die Wirkung des Methylenblau bei Malaria. Berlin Klin Wochenschr 28:953–956Google Scholar
- 25.Pauli-Magnus C, Lacayo CI, Kroetz DL (2001) Antimalarial drugs are not substrates of human P-glycoprotein. Clin Pharmacol Ther 69:P76Google Scholar