The potential use of methotrexate in the treatment of falciparum malaria: in vitro assays against sensitive and multidrug-resistant falciparum strains.

The anti-malarial activity of the anti-cancer drug methotrexate against chloroquine-sensitive T9-96 and the multidrug-resistant K1 strains of Plasmodium falciparum was assessed in vitro. Mean IC50 values of 0.32 +/- 0.05 nM and 48.02 +/- 4.40 nM were obtained for T9-96 and K1, respectively, indicating methotrexate's high potency against both sensitive and resistant P. falciparum strains in vitro. Our results suggest that methotrexate is potentially effective against falciparum malaria in short-term, low-dose regimens, minimizing the risk of toxicity. This, along with the practical advantages of methotrexate, warrants the clinical investigation of methotrexate in human cases of falciparum malaria.