WHO Model Prescribing Information: Drugs Used in Parasitic Diseases - Second Edition
(1995; 152 pages) [French] [Spanish] View the PDF document
Table of Contents
View the documentPreface
Open this folder and view contentsProtozoa
Close this folderHelminths
Open this folder and view contentsCestode (tapeworm) infection
Close this folderIntestinal nematode infection
View the documentAlbendazole
View the documentLevamisole
View the documentMebendazole
View the documentPiperazine
View the documentPyrantel
View the documentTissue nematode infections
Open this folder and view contentsLoiasis
Open this folder and view contentsLymphatic filariasis
Open this folder and view contentsOnchocerciasis
Open this folder and view contentsSchistosomiasis
Open this folder and view contentsIntestinal, liver and lung flukes
View the documentSelected WHO publications of related interest
View the documentBack cover


Group: anthelminthic agent
Tablet 40 mg, 50 mg (as hydrochloride)
Syrup 40 mg/5 ml

General information

Levamisole, the (-)-isomer of tetramisole, acts by paralysing the musculature of susceptible nematodes. Unable to maintain their anchorage, the worms are ejected by normal peristaltic action, usually within 24 hours.

Levamisole is rapidly and almost completely absorbed from the gastrointestinal tract. Peak plasma concentrations occur within 2 hours and the plasma half-life is about 4 hours. It is extensively metabolized in the liver and is excreted in the urine as metabolites and unchanged drug.

Clinical information


Treatment of ascariasis and mixed ascariasis/hookworm infections.

Dosage and administration

Adults and children: a single dose of 2.5 mg/kg is used widely for both individual treatment and community-based campaigns. In cases of severe hookworm infection a second standard dose may be given 7 days after the first.


In the doses recommended for treatment of helminthic infections there are no absolute contraindications.

Use in pregnancy

Animal studies have provided no evidence of teratogenicity. Although high priority should be accorded to the treatment of pregnant women, levamisole should preferably not be administered during the first trimester.

Adverse effects

Abdominal pain, nausea, vomiting, dizziness and headache are occasionally reported.


Emesis or gastric lavage may be of value if undertaken within a few hours of ingestion. Treatment is otherwise symptomatic and supportive.


Tablets and syrup should be stored in well-closed containers.

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