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 500 mg hydrate (as citrate or adipate)
Elixir (as citrate) equivalent to 500 mg hydrate/5 ml

General information

Piperazine may selectively block neuromuscular cholinergic receptors in Ascaris lumbricoides and Enterobius vermicularis, but this has not been demonstrated conclusively.

It is readily absorbed but the plasma half-life is highly variable. Some is metabolized in the liver and the remainder is excreted unchanged in the urine.

Clinical information


Treatment of ascariasis and enterobiasis.

Dosage and administration


The following schedule is commonly used both in treating individuals and in community-based campaigns:

Adults and children over 12 years: 75 mg/kg to a maximum of 3.5 g.

Children between 2 and 12 years: 75 mg/kg to a maximum of 2.5 g.

Children under 2 years: 50 mg/kg administered under medical supervision.

These amounts are often taken in a single dose between meals, but it has been claimed that better results are obtained when the total dose is divided and taken over two consecutive days.


Adults and children: 50 mg/kg on each of 7 successive days. This course is repeated after an interval of 2 to 4 weeks.

It is advisable to treat all members of the household concurrently.


• Known hypersensitivity.
• Epilepsy.
• Renal or hepatic impairment.


Treatment should be discontinued if hypersensitivity or severe intolerance develops, or if neurological signs occur.

Drug interactions

Piperazine and pyrantel are antagonistic in their mechanisms of action. They should never be administered together.

Concurrent administration of chlorpromazine has been reported to potentiate the risk of seizures.

Use in pregnancy

Safe use in pregnancy has not been established. Although high priority should be accorded to the treatment of pregnant women, piperazine should preferably not be administered during the first trimester.

Adverse effects

Gastrointestinal irritation occasionally occurs.

Hypersensitivity reactions, including skin rashes, fever and joint pains are not uncommon. When they occur, treatment should be withdrawn immediately and the patient warned against taking piperazine again.

Transient neurological symptoms may also occur, particularly dizziness, paraesthesia and slight incoordination. Epilepsy and neuropsychiatric conditions may be exacerbated.


Overdosage can result in convulsions, respiratory depression and transient paresis of the limbs.

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


Tablets and elixir should be stored, protected from light, in tightly closed containers.

to previous section
to next section
The WHO Essential Medicines and Health Products Information Portal was designed and is maintained by Human Info NGO. Last updated: October 29, 2018