Levamisole in ascariasis. A multicenter controlled evaluation.

An analysis is presented of 10 clinical studies from various countries where levamisole 50--150 mg was compared to pyrantel, piperazine, and placebo in a total of 1,734 patients, mostly children (levamisole: 830, controls: 904), suffering from ascariasis either as a single infection or usually mixed with other nematode infections. Degree of infection and efficacy of treatment were determined by quantitative coproparasitological methods. Levamisole produced higher cure rates (91%) and egg reduction rates (98%) than pyrantel, piperazine, or placebo. The efficacy of levamisole was unrelated to the patients' sex and age, the severity of infection, the presence of another worm infection, the type of associated worm infections, or the egg-counting technique. The overall incidence of reported adverse reactions was lower after levamisole than after piperazine, pyrantel or placebo; abdominal pain and headache, the most frequent complaints after levamisole, were related to the initial severity of ascariasis. Follow-up examinations 6 months after treatment suggested that levamisole might delay reinfection.