Albendazole versus placebo in treatment of echinococcosis.

Echinococcus granulosus infection can have multiorgan involvement, and is common in Third-World countries. Uncontrolled studies show that albendazole can be effective in its treatment, but there are also reports of spontaneous resolutions. We therefore undertook a placebo-controlled double-blind parallel-group randomized study in Iran to evaluate the effect of albendazole on hydatid cysts. Twenty-nine patients with 240 cysts entered the study in 1994-95 and received either albendazole (400 mg twice a day, in 3 cycles of 6 weeks with 2 weeks between cycles) or placebo. At study completion, 172 and 31 cysts in the albendazole and placebo groups, respectively, were evaluable. In the treatment arm, 134 cysts showed improvement or cure compared to 4 in the placebo group (P < 0.001). Eighteen (82%) of 22 patients in the treatment arm showed either cure (8 patients) or improvement (10 patients); in the placebo group only 1 (14%) of 7 showed spontaneous improvement but no cure. Some patients with liver cysts after treatment showed increasing heterogeneity and density suggestive of inactive cysts. Patients with larger cysts and those with pulmonary involvement were better responders. Age and gender had no effect on outcome. The observed results are encouraging, showing albendazole has good effect on hydatid cysts and should be offered to patients before surgical treatment is considered.