In vitro effects of co-incubation of blood with artemether/lumefantrine & vitamin C on the viscosity & elasticity of blood

Abstract

Background & objectives:The antimalarial combination drug artemether/lumefantrine has been shown to be effective against malaria parasite through its haemolytic action. This drug is sometimes co-administered with vitamin C in patients with malaria. Vitamin C is associated with antioxidant properties which would be expected to protect against haemolytic effects of this antimalarial drug. This study was designed to investigate in vitro effects of co-incubation of artemether/lumefantrine with vitamin C on the viscosity and elasticity of blood.Methods:Blood was collected from 12 healthy female volunteers with normal haemoglobin genotype (HbAA). A Bioprofiler was used to measure the viscosity and elasticity of untreated blood samples (control) and samples exposed to artemether/lumefantrine (0.06/0.36 mg/ml) alone and with low or high dose vitamin C (equivalent to adult doses of 100 or 500 mg).Results:Artemether/lumefantrine significantly (P<0.05) reduced viscosity of blood from 4.72 ± 0.38 to 3.78 ± 0.17 mPa.s. Addition of vitamin C (500 mg) further reduced blood viscosity to 2.67 ± 0.05 mPa.s. The elasticity of blood was significantly (P<0.05) reduced from 0.33 ± 0.04 mPa.s to 0.24 ± 0.03 mPa.s by the antimalarial drug, and further reduced to 0.13 ± 0.02 mPa.s in the presence of vitamin C (500 mg).Interpretation & conclusions:Co-incubation of blood with vitamin C and antimalarial combination drug potentiates the haemolytic effects of the latter on reducing blood viscosity and elasticity in vitro. This may possibly have implications in relation to haemolysis in patients receiving vitamin C supplementation with artemether/lumefantrine during malaria therapy.

Ascorbic acid coadministration with artesunate–amodiaquine, up-regulated antioxidant enzymes gene expression in bone marrow cells and elicited biochemical changes in Plasmodium berghei-infected mice

“…Haemolysis has been associated with high levels of bilirubin [37,38]. Previous study have shown that when blood was incubated with a therapeutic dose of artemether-lumefantrine and high/low concentrations of ascorbic acid, its viscosity and elasticity were significantly reduced [42]. This decrease in elasticity and viscosity may have resulted from low haematocrit caused by haemolysis [39].…”

Ascorbic acid co-administration with artemisinin based combination therapies in falciparum malaria

“…In the article by McKoy et al 14 in this issue, the authors designed an in vitro study to observe the effects of co-incubation of artemether/lumefantrine combination (Coartem ® ) with vitamin C on the viscosity and elasticity of blood. The study was conducted on blood samples from 12 healthy female volunteers free from sickle cell disease/trait.…”