A randomized trial of single- and two-dose ivermectin versus thiabendazole for treatment of strongyloidiasis

A randomized trial is described comparing ivermectin and thiabendazole for treatment of chronic infection with Strongyloides stercoralis. Subjects received ivermectin (200 IJ,g/kg) in a single dose, ivermectin (200 IJ,g/kg) on 2 consecutive days, or thiabendazole (50 mg/kg/day) twice daily for 3 consecutive days. Most subjects (94%) had intermittent symptoms, including urticaria, epigastric pain, and diarrhea. Stools were examined 7 days and I, 3, 6, 10, and 22 months after treatment. Fifty-three subjectscompleted at least 3 months of follow-up. Only 1 of 34 and 2 of 19 ivermectin and thiabendazole subjects, respectively, had a stool positive for larvae after treatment. Symptoms were relieved inall 3 groups and eosinophil levelsreturned to normal in 90 % of all subjects by 12 months. Nearly 95 % of thiabendazole subjects had short-term adverse effects during therapy versus only 18 % of those treated with ivermectin. One dose of ivermectin provides safety and efficacyequivalentto thiabendazolewith a much lowerprevalence of side effects and, consequently, better compliance. Chronic infection with Strongyloides stercoralisis a world-wide problem that presents both diagnostic and therapeutic challenges. Accurate estimates of the prevalence of infectio