Monitoreo in vitro de la susceptibilidad del Plasmodium falciparum a cinco drogas antimalaricas: Estado Amazonas, Venezuela

the susceptibility of isolates of plasmodium falciparum of the municipality atures in amazonas state, venezuela, to five antimalarial drugs was evaluated using the schizont maturation inhibition technique (oms mark ii). parasites were sensible to: 64 pmol mefloquine in 56/56 isolates; 256 pmol of quinine in 56/60 isolates; 1000 pmol of sulfadoxinepyrimethamine in 15/22 isolates; 4 pmol of amodiaquine in 34/59 isolates; 8 pmol of chloroquine in 34/58 isolates. the values of the 50% inhibition concentration (ic50, geometric mean) were as follows: mefloquine = 1.11pmol; quinine = 7.60 pmol; sulfadoxine-pyrimethamine = 21.60 pmol; chloroquine= 1.23 pmol; amodiaquine = 0.66 pmol. the present study confirms full sensibility of the strains to mefloquine, and decreasing sensibility to quinine, chloroquine, amodiaquine and sulfadoxine-pyrimethamine. the susceptibility of p. falciparum to antimalarial drugs needs continuous monitoring in order to detect the emergence of resistant strains and to guarantee the quality of the malaria control programme of amazonas, venezuela.