Effect of ketotifen on the ultrastructure of the erythrocytic stages of Plasmodium yoelii.

The effect on the morphology of Plasmodium yoelii of ketotifen treatment was different from that of chloroquine and other antimalarial drugs. Following administration of a low dosage of ketotifen, the parasite first developed a multilamellate pellicular complex which resembled a medullary sheath and then developed vacuoles and cavitations. The development of large multilamellate whorls consisting of a pellicular structure enclosing cytoplasm was the typical change which occurred.