Abstract

P.C. Chikezie

In the present in-vivo study, the capacities of five antimalarial drugs (Fansidar, Halfan, Quinine, Coartem and Chloroquine phosphate) to alter/distort methaemoglobin concentrations of three human erythrocyte genotypes (HbAA, HbAS and HbSS) was investigated. Spectrophotometric method was used to ascertain this erythrocyte parameter. The male participants enrolled for this study were grouped according to their genotypes, pathologic status, (that is, non-malarious and malarious individuals). Determination of erythrocyte methaemoglobin concentration was carried out before (control; t = 0 h) and after (tests; that is, at t = 3, 6 and 18 h) the five (5) antimalarial drugs were administered to various corresponding groups of participants. The results showed that methaemoglobin concentrations of these individuals ranged between 1.45+/-0.13 and 2.50+/- 0.43%; 8.27+/-2.41 and 14.78+/-2.45%, for non-malarious and malarious male individuals respectively. There was no significant difference (p > 0.05) between methaemoglobin concentrations of HbAA and HbAS erythrocyte of non-malarious participants. The doses of the five antimalarial drugs administered to nonmalarious individuals did not cause toxic methaemoglobinemia. Under the same experimental conditions, erythrocytes obtained from persons of HbSS genotype exhibited significant (p < 0.05) elevation of methaemoglobin concentration. Relatively high levels of methaemoglobin concentration of parasitized red blood cells decreased in a time dependent manner after administration of the five antimalarial drugs. Therefore, erythrocyte methaemoglobin evaluation is a reliable biochemical marker and rational for diagnostic and therapeutic potential in malaria. Furthermore, moderate increases of erythrocyte methaemoglobin in HbSS individuals served as point of caution when administering these drugs to this category of human subjects.