Single dose therapy of ascariasis--a randomized comparison of mebendazole and pyrantel.

A multicentre, randomized trial was carried out to compare the efficacy of two single-dose treatments for ascariasis: mebendazole 200 mg, and pyrantel 10 mg/kg. Each centre enrolled 200 patients with a suspected diagnosis of ascariasis, 100 for each treatment, and the treatments were randomized for each centre. To confirm the diagnosis, stools were examined for eggs of Ascaris lumbricoides by Kato's thick smear method. Efficacy was evaluated by stool examination repeated three weeks after treatment by a "blind" technician using two methods, viz. Kato's thick smear method and the zinc sulfate flotation method. Cure was defined as absence of ascaris eggs in the stools by both methods. Of the 600 enrolled patients, 32 were excluded from analysis as their initial stool examination was negative, and 568 completed the trial: 284 on each treatment. The cure rate was 80 per cent in the mebendazole group and 90 per cent in the pyrantel group (P less than 0.01). Thus pyrantel was found to be significantly more efficacious than mebendazole for single-dose treatment of ascariasis.