Hycanthone dose-response in treatment of Schistosomiasis mansoni in St. Lucia

ABSTRACT

Clinical trials of hycanthone (single intramuscular dose) were undertaken in Schistosomiasis mansoni patients in St. Lucia at five dose levels 3.0, 2.5, 2.0, 1.5, and 1.0mg/kg body weight. The most common side effect, vomiting, decreased in frequency from 51 percent at the highest dose to 3 percent at the lowest; minor side effects showed a similar trend. Three fecal specimens were examined before and at 6 months after treatment by qualitative, quantitative, and hatching techniques. All dose levels caused reductions in egg excretion of 89 to 98 percent. Rates of cure (absence of eggs by all three methods) according to dose(descending), pretreatment egg output (0-19, 20-49, 50-399, 400+ eggs/ml feces), and age (0-7, 8-14, 15-29, 30+ years) were analyzed to estimate the effect of each variable if the others had been constant. For dose, the standardized percentage success rates were 53.9 percent, 62.0 percent, 51.2 percent, 54.0 percent, and 27.4 percent; for egg output, 67.0 percent, 51.8 percent, 43.2 percent, and 21.7 percent; and for age, 25.2 percent, 34.5 percent, 59.3 percent, and 57.4 percent. Logit regression analysis shows a significant difference in cure rate (a) between the lowest dose and all others, among which latter there was no difference, (b) between patients excreting 0 to 49 eggs/ml before treatment and those excreting 50+ eggs/ml, and (c) between the age groups 0 to 14 and 15+ years. All dose levels caused some regression in enlargement of liver and spleen. A dose of 1.5 to 2.0mg/kg body weight is considered to be as effective as one of 3.0mg/kg and more acceptable for a control program because of the marked reduction in side effects. (AU)