The chemotherapy of amoebiasis

The dramatic effectiveness of injectable emetine in amoebic dysentery and amoebic liver abscess was first demonstrated by Leonard Rogers in India in 1912. The previous year, Vedder had shown that emetine was the principal active alkaloid in ipecacuanha, the powdered root of the Brazilian plant, Cephaelis ipecacuanha, which had been brought back to Europe by Williams Piso in 1658. Doses of ipecacuanha large enough to be really effective in dysentery were used in India from 1858 onwards but usage was often limited by the emetic qualities of the drug that were later to give the principal alkaloid its name. Emetine remains a useful drug to this day and is still our most potent amoebicide. Although a miscellany of drugs destroy Entamoeba histolytica within the colonic lumen, the number of tissue amoebicides, used to treat invasive disease, is still relatively limited; chloroquine was introduced for hepatic amoebiasis in 1948, synthetic dehydroemetine in 1959 and the schistosomicidal drug niridazole in 1966. The second major milestone in therapy was the demonstration that metronidazole, a drug used for trichomoniasis since 1958, was effective in invasive amoebiasis (Powell et ai, 19666). Numerou