Antidepressant drugs suppress growth of the human pathogenic protozoan Giardia lamblia.

The tricyclic antidepressant drug chlorimipramine, some of its congeners, and its mammalian metabolites inhibited the growth in vitro of the human intestinal pathogen Giardia lamblia. The inhibitory action may reside in their ability to inhibit the membrane-associated ATPase characteristic of eukaryotes. Synthesis of other compounds of the tricyclic class may produce drugs of potential therapeutic use in the treatment of giardiasis and possibly other protozoal diseases.