Figure 1.

Evolution of the 8-aminoquinoline hypnozoitocides, including the winnowing out of irreversible severe neurotoxicity of plasmocid and related compounds distinguished by fewer than four methylene groups separating the amino groups of the alkyl chain at the defining 8-amino position. Plasmochin and others (including primaquine) having at least four methylene groups exhibited no such neurotoxicity but instead reversible toxicity at sub-lethal doses involving principally hepatic, hematological and gastrointestinal systems