Antimalarial effect in vitro and lack of modulating effect of desipramine and imipramine.

Based on previous studies in vitro of the modulating effect of desipramine on chloroquine-resistance of Plasmodium falciparum, the effect of desipramine and imipramine on freshly isolated resistant Brazilian strains of the parasite was investigated. Both drugs in therapeutic doses showed an unexpected antimalarial effect in vitro in duplicate tests (IC50 = 44.26 and 46.53 micrograms/L for desipramine, and 83.93 and 41.26 micrograms/L for imipramine), but no reversal of resistance when added to cultures together with chloroquine.