Chemoresistance of Plasmodium falciparum in urban Yaounde (Cameroon). PartTwo: Evaluation of the efficacy of amodiaquine and a combined sulfadoxine-pyrimethamine preparation for the treatment of simple malaria due to Plasmodium falciparum in Yaounde (Cameroon)

The spread of chloroquine resistance or its stabilization at a high level c alls for a change in the therapeutic strategy, including a possible replace ment of chloroquine. We assessed and compared the efficacy of amodiaquine a nd sulfadoxine-pyrimethamine in Yaounde. Of 140 adults and children > 5 yea rs enrolled in the study, 59 in the amodiaquine and 58 in the sulfadoxine-p yrimethamines treatment group were followed until day 14. The efficacy of a modiaquine was 100%, whereas 12.1% of the patients treated with sulfadoxine -pyrimethamine responded with an early treatment failure. Side effects in B oth treatment groups were mild and did not require any specific treatment. We did in vitro drug assays for monodesethylamodiaquine (active metabolite of amodiaquine) and pyrimethamine and measured plasma levels of monodesethy lamodiaquine, sulfadoxine, and pyrimethamine. Unlike amodiaquine, the resul ts of the in vitro drug sensitivity rest for pyrimethamine were not concord ant with the clinical response. A wide inter-individual variation in the pl asma drug levels was observed. Unlike chloroquine, the mean plasma concentr ations did not vary with age. There was no significant difference in the pl asma concentrations of sulfadosine and pyrimethamine between patients respo nding with an adequate clinical response and those responding with treatmen t failure. Amodiaquine has several advantages over sulfadoxine-pyrimethamin e combination and may be considered to be an effective drug in an endemic z one with a moderate level of chloroquine resistance.