Clinically available antischistosomal drugs

The indications, the contraindications, and the characteristics of the antimonial and nonantimonial drugs clinically available for the treatment of human schistosomiasis are outlined. Of the antimonial compounds, antimony potassium tartrate or antimony sodium tartrate, both given by the intravenous route, are effective against Schistosoma japonicum, S. mansoni, and S. hematobium, but the production of severe side effects limits their use outside the treatment of individuals. Sodium antimonyl gluconate is less effective against S. mansoni and S. hemotobium and is also given intravenously. Of those antimonial compounds given intramuscularly, antimony dimercaptosuccinate is the most effective against all three common human schistosomes. Four available nonmetallic schistosomicides are considered. Niridazole, orally administered, is effective against all three common species of schistosome infecting man, but activity is maximal against S. hematobium. Many minor side effects have been described, but the major and most important side effects, neuropsychiatric symptoms and signs, are fortunately rare. Lucanthone hydrochloride, of moderate efficiency when given orally for S. hematobium or S. mansoni infections, is probably best used as a suppressant in small doses. Troublesome gastrointestinal toxicity limits its therapeutic use. Metrifonate, a cholinesterase-inhibiting organophosphorus compound, is effective only against S. hematobium. Clinical tolerance is very good. Hycanthone mesylate is highly effective against S. mansoni and S. hematobium but ineffective against S. japonicum. It is given as a single intramuscular dose. Many contraindications to its use exist, and acute hepatotoxicity has occurred infrequently. Its association with mutagenicity in certain experimental test systems has stimulated numerous ongoing studies to clarify the implications of its use in humans.