Oxantel is an anthelmintic active ingredient used in veterinary and human medicine. It is used in dogs and cats against internal parasites (mainly roundworms). It is not used against agricultural and household pests. It belongs to the chemical class of the tetrahydropyrimidines.

Common name: OXANTEL

Type: veterinary medecine
Chemical class: tetrahydropyrimidine


Molecular structure of OXANTEL 



Type of action: Anthelmintic endoparasiticide.
Main veterinary parasites controlled: Gastrointestinal roundworms = nematodes

Efficacy against a specific parasite depends on the delivery form and on the dose administered. 

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Oxantel is a narrow-spectrum anthelmintic effective against whipworms in dogs en cats. It is ineffective against other roundworms, flukes, tapeworms or external parasites. Oral administration is the rule. It is used moderately in dogs and cats (mainly in the form of tablets or oral suspensions), almost always in combination with other broad-spectrum nematicides (e.g. pyrantel). It is not used in livestock or horses.

The table below indicates some usual dosing recommendations for oxantel issued by manufacturers or documented in the scientific literature. They may not be approved in some countries.

Dosing recommendations for OXANTEL
Delivery Parasites Dose (against oxantel-susceptible parasites)
Oral Trichuris spp 15-55 mg/kg
Oral Trichuris spp 15-55 mg/kg

DISCLAIMER: Liability is denied for any possible damage or harm to persons, animals or any other goods that could follow the transmission or use of the information, data or recommendations in this site by any site visitor or third parties.

Dosing recommendations for antiparasitics depend on national regulations. National regulatory authorities determine whether a product is approved for a given indication, i.e. use on a particular host at a specific dose and against a specific parasite. Check the labels of the products available in your country for specific information on approved indications.


Oral LD50, rat, acute*: embonate: 170 mg/kg; pamoate >2000 mg/kg
Dermal LD50, rat, acute*: not found
* These values refer to the active ingredient. Toxicity has to be determined for each formulation as well. Formulations are usually significantly less toxic than the active ingredients.

MRL (maximum residue limit): Not applicable, not approved for use on livestock.
Withholding periods for meat, milk, eggs, etc.: Not applicable, not approved for use on livestock.

Learn more about oxantel safety (poisoning, intoxication, overdose, antidote, symptoms, etc.).

General safety information for antiparasitics is available in specific articles in this site (click to visit):


It is obvious that veterinary products are not intended for and should never be used on humans!!!


Decade of introduction: 1970
Introduced by: PFIZER → ZOETIS
Some original brands: TELOPAR
Patent: Expired (particular formulations may be still patent-protected)

Use in HORSES: No
Use in DOGS and CATS: Yes, very scarce
Main delivery forms: 

Use in human medicine: Yes, in some countries
Use in public/domestic hygiene: No
Use in agriculture: No
Generics available:  Yes,  quite a few


In pets: No. It seems that oxantel has a slightly different mode of action than other tetrahydropyrimidines (pyrantel and morantel) and may not have cross-resistance with them.

Learn more about parasite resistance and how it develops.


Oxantel is a veteran, narrow-spectrum nematicide closely related to pyrantel and morantel, all belonging to the tetrahydropyrimidines. It is mostly used in the form of various salts (embonate, pamoate, etc.).

It is only used in dogs and cats in the from of drenches or tablets, pills, etc. almost always in combination with other anthelmintics, typically pyrantel, sometimes also praziquantel to add taenicidal efficacy.

Oxantel is not used in livestock.

Efficacy of oxantel

Oxantel is particularly effective against parasitic worms in the large intestine, typically whipworms (Trichuris spp). The reason is that oxantel goes almost unabsorbed through the gastrointestinal tract and reaches rather high concentrations in the large intestine, the preferential site of whipworms.

Efficacy against other adult gastrointestinal roundworms is usually insufficient; this is why it is almost always used together with pyrantel

Oxantel has no residual effect. This means that a single administration will kill the parasites present in the host at the time of treatment, but it will not protect the host against re-infestations.

Oxantel has no efficacy whatsoever against non-gastrointestinal roundworms (pulmonary, skin, eyes, etc.), flukes (i.e. trematodes), and tapeworms (i.e. cestodes).

Mechanism of action of oxantel

Tetrahydropyrimidines, including oxantel, act on the nervous system of the worms as inhibitors of acetylcholinesterase (also known as AchE), an enzyme that hydrolyzes acetylcholine (Ach).

Ach is a molecule involved in the transmission of nervous signals from nerves to muscles (so-called neuromuscular junctions) and between neurons in the brain (so-called cholinergic brain synapses). AchE's role is to terminate the transmission of nervous signals where acetylcholine is the neurotransmitter (there are several other neurotransmitters). Inhibition of AchE massively disturbs the normal movements of the parasites.

The bottom line for the parasitic worms is that they are paralyzed and die more or less quickly, or are expelled from the gut because they cannot keep themselves attached to the intestinal wall.

However, whereas other tetrahydropyrimidines such as pyrantel and morantel act on the so-called L-subtype cholinergic receptors (sensitive to pyrantel and levamisole), oxantel acts on the so-called N-subtype cholinergic receptors (sensitive to nicotine and methyridine).

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