The in vitro effects of sulfadoxine/pyrimethamine and artemether/lumefantrine on the viscoelasticity of erythrocyte membrane of healthy females.

Fansidar® (sulfadoxine/pyrimethamine) and Coartem® (artemether/lumefantrine) are drugs that destroy malarial parasites and also produce free radicals which cause hemolysis of malaria-parasitized erythrocytes. This study investigated the effect of these drugs on the viscoelasticity of erythrocytes of ten healthy female subjects using the BioProfiler. The concentration for each of the two drugs were determined based on the therapeutic dose as normal, half the therapeutic dose as low and double the therapeutic dose as high. For Fansidar®, the concentrations were 0.15/0.01 mg/ml (low), 0.30/0.02 mg/ml (normal) and 0.60/0.04 mg/ml (high) based on the adult therapeutic dose of 1500/75 mg of sulfadoxine/pyrimethamine in the drug combination. For Coartem®, the concentrations were 0.03/0.19 mg/ml (low), 0.06/0.38 mg/ml (normal) and 0.12/0.76 mg/ml (high) based on the adult therapeutic dose of 320/1920 mg of artermether/lumefantrine in the drug combination. There was a statistically significant (p < 0.05) decrease in viscosity, elasticity and relaxation time with Coartem® at normal and high doses. Fansidar® also showed significant (p < 0.05) reductions in these parameters only in the high dose. This suggests that Coartem® generated significant free radicals at normal and high doses, with Fansidar® only in the high dose, resulting in increased hemolysis and ultimately reduced viscoelasticity.