The effect of emetine hydrochloride, dehydroemetine, Ambilhar, metronidazole, and chloroquine on the electrocardiogram of African patients with invasive amebiasis was compared. Flattening or inversion of the T wave and prolongation of the QTc interval were by far the most frequent changes encountered and were common among those who received emetine hydrochloride, dehydroemetine, and Ambilhar. With the latter drug the changes were more transient, but a combination of Ambilhar and dehydroemetine produced severe abnormalities. Metronidazole and chloroquine caused relatively few changes.
Although significant clinical cardiac toxicity has been rare with all the drugs studied, the electrocardiographic findings confirm the wisdom of elementary precautions in the use of emetine hydrochloride and dehydroemetine. In the presence of heart disease these preparations are contraindicated, and Ambilhar should only be given with caution. In addition to being a suitable replacement for chloroquine, metronidazole promises to be a uniquely safe and effective amebicide in such patients.
The Amoebiasis Research Unit is sponsored by the following bodies: The South African Council for Scientific and Industrial Research, The Natal Provincial Administration, The University of Natal, and the United States Public Health Service (Grant AI-01592).