PRELIMINARY TRIALS WITH PRAZIQUANTEL IN HUMAN INFECTIONS DUE TO SCHISTOSOMA-MANSONI

Abstract

As part of a program of multicenter trials of the tolerance and therapeutic effect of praziquantel, clinical trials were carried out in Brazil in patients with active S. mansoni infections, each of whom had a minimum geometric mean egg output of 100 eggs/g of feces calculated from multiple pretreatment stool examinations. The 1st stage was a double-blind assessment of tolerance and efficacy of oral doses of 1 .times. 20, 2 .times. 20 or 3 .times. 20 mg of praziquantel/kg of body wt. Subsequently, single-blind trials explored the effects of 3 .times. 20 mg/kg at 4 h intervals, and a single dose of 50 mg/kg. Side effects increased in frequency as dosage increased. Nausea, epigastric pain, headache, dizziness and drowsiness were all noted, but their severity was mild or moderate and they disappeared in 48 h. In general, monitoring laboratory tests showed little change. Following a stringent parasitological follow-up, 96% of 28 patients followed at 1 yr after treatment with either 3 .times. 20 mg/kg or 1 .times. 50 mg/kg were cured. Praziquantel seems to be a very promising drug against S. mansoni and further clinical trials should be strongly encouraged.