Pyrantel pamoate
Anthelmintics
Anthelmintics
Oral worm medicine that paralyses intestinal roundworms; used for pinworm, Ascaris and hookworm, and sold without prescription in some countries.
Also called: pyrantel embonate, pyrantel
Quick facts
- Group
- Anthelmintics
- Target
- Nematode nicotinic acetylcholine receptors (L-type) of body-wall muscle
- Used for
- Enterobiasis · Ascariasis and hookworm infection
- Key effects
- Abdominal cramps · Loss of appetite · Rash and fever
- Monitor
- Persistent anal itching
- ATC
- P02CC01
No doses: the clinician sets them by the current guideline.
Mechanism of action
Pyrantel is a depolarising neuromuscular blocker for worms. It opens the nicotinic acetylcholine receptors of the worm's muscle and keeps them open, so the muscle stays contracted (spastic paralysis). The paralysed worms lose their grip on the bowel wall and are passed in the stool. Very little is absorbed, so the drug acts only on worms in the gut lumen.
- Activates the worm's muscle nicotinic acetylcholine receptors
- The muscle depolarises and stays contracted (spastic paralysis)
- Paralysed worms lose their hold on the bowel wall
- Worms are expelled in the stool
Indications
- Enterobiasis (pinworm), with a repeat dose after two weeks and treatment of the household
- Ascariasis and hookworm infection Soil-transmitted helminthiasis (ascariasis, hookworm, trichuriasis) →
Adverse effects
- Abdominal cramps, nausea, vomiting and diarrhoea
- Loss of appetite
- Headache and dizziness
- Rash and fever, occasionally
Contraindications
- Allergy to pyrantel
- Liver disease, unless a clinician directs its use
Key interactions
- Oxantel pamoate
- Combined for mixed infections with whipworm (Trichuris), which pyrantel alone does not cover.
- Food
- No meaningful effect; it can be taken with or without meals.
What is monitored
- Persistent anal itching or visible worms after treatment
- Cure checked after the second dose in pinworm infection
Administration and safety
- Oral suspension, liquid or tablets; the suspension is shaken well
- For pinworm the dose is repeated after two weeks, because eggs hatch after the first dose
- Children under two years only on medical advice
Pregnancy and breastfeeding
It has not been studied in pregnant women; labels advise using it in pregnancy only when a clinician directs.
Nursing care
- Treat the whole household when one member has pinworm, unless advised otherwise
- Teach hand washing, short nails, daily morning showers and hot washing of bedding and underwear
- Ask about liver disease, anaemia, pregnancy and breastfeeding
- Report symptoms that persist after treatment
Pharmacokinetics
- Absorption
- Poorly absorbed from the gut, which keeps its action in the bowel lumen; taken with or without food.
- Elimination
- Most of the dose leaves unchanged in the faeces; a small part is excreted in the urine.
Test yourself
Think of the answer, then tap the question to see it.
How does pyrantel paralyse intestinal worms?
It activates the worm's muscle nicotinic acetylcholine receptors and keeps them open, causing spastic paralysis.
Why is pinworm treatment with pyrantel repeated after two weeks?
The first dose does not kill the eggs; the second dose kills worms that hatched in the meantime and reinfections.
Why does pyrantel act only on worms in the bowel lumen?
It is poorly absorbed, so most of the dose stays in the gut and leaves in the faeces.
What is done for the household of a child with pinworm?
Usually the whole household is treated, along with hand washing, short nails and hot washing of bedding.
Connections
← Back to the class: Anthelmintics
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - PYRANTEL PAMOATE suspension (DailyMed (U.S. National Library of Medicine), 2026); Pyrantel: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); eEML - Electronic Essential Medicines List (World Health Organization (WHO), 2026).
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Representative model, for educational purposes only.