Pyrantel pamoate

Description

Pyrantel is a tasteless, odorless, yellow, crystalline solid. It is insoluble inwater, slightly soluble in dimethylformamide, and soluble in dimethyl sulfoxide.

Chemical properties

Pale yellow or yellow powder.

The Uses of Pyrantel pamoate

anthelmintic

The Uses of Pyrantel pamoate

An antiparasitic agent used in the treatment of intestinal parasites such as hookworms and roundworms (Ascaris lumbricoides, aka ascarids in humans) in domesticated animals such as horses, cattle, sheep, pigs, cats, dogs, and many other species.

What are the applications of Application

Pyrantel Pamoate is an anthelmintic compound

Indications

Pyrantel pamoate (Antiminth) is a agonist at the nicotinic acetylcholine receptor, and its actions result in depolarization and spastic paralysis of the helminth muscle. Its selective toxicity occurs primarily because the neuromuscular junction of helminth muscle is more sensitive to the drug than is mammalian muscle. This drug is administered orally, and because very little is absorbed, high levels are achieved in the intestinal tract. Less than 15% of the drug and its metabolites are excreted in urine.

Definition

ChEBI: Pyrantel pamoate is an organic molecular entity.

brand name

Antiminth (Roerig); Combantrin (Pfizer).

General Description

Odorless light yellow to tan crystalline powder. Tasteless. Used medicinally against nematodes in animals.

Air & Water Reactions

May be sensitive to prolonged exposure to air and light . Insoluble in water.

Reactivity Profile

Pyrantel pamoate may react with acids to liberate heat. May react exothermically enough with strong oxidizing acids to ignite the reaction products. Heat is also generated with caustic solutions. Generates flammable or toxic gases with alkali metals and hydrides and other reducing agents.

Fire Hazard

Flash point data for Pyrantel pamoate are not available; however, Pyrantel pamoate is probably combustible.

Mechanism of action

Pyrantel is a depolarizing neuromuscular blocking agent. In nematodes it causes a slowly developing contraction and paralysis. The immobilized parasites are then eliminated from the intestine. The neuromuscular junction of Ascaris is 100-fold more sensitive to pyrantel than to acetylcholine .

Clinical Use

Trans-1,4,5,6,-Tetrahydro-1-methyl-2-[2-(2 -thienyl)ethenyl]pyrimidine pamoate (Antiminth) is a depolarizing neuromuscularblocking agent that causes spastic paralysis insusceptible helminths. It is used in the treatment of infestationscaused by pinworms and roundworms (ascariasis).Because its action opposes that of piperazine, the twoanthelmintics should not be used together. More than halfof the oral dose is excreted in the feces unchanged.Adverse effects associated with its use are primarilygastrointestinal.

Side Effects

Pyrantel pamoate is active against several roundworms: A. lumbricoides, Ancylostoma duodenale, Necator americanus, and E. vermicularis. Pyrantel is an alternative drug of choice in treating infections with A. lumbricoides, E. vermicularis (pinworms), and hookworms (N. americanus and A. duodenale). It is not recommended for pregnant patients or for children under age 1 year.
Although most of the drug remains in the intestinal lumen, enough can be absorbed systemically to cause headache, dizziness, and drowsiness. No major adverse effects have been reported on renal, hepatic, or hematological systems.

Veterinary Drugs and Treatments

Pyrantel has been used for the removal of the following parasites in dogs: ascarids (Toxocara canis, T. leonina), hookworms (Ancylostoma caninum, Uncinaria stenocephala), and stomach worm (Physaloptera). Although not approved for use in cats, it is useful for similar parasites and is considered safe to use.
Pyrantel is indicated (labeled) for the removal of the following parasites in horses: Strongylus vulgaris and equinus, Parasacaris equorum, and Probstymayria vivapara. It has variable activity against Oxyuris equi, S. edentatus, and small strongyles. Pyrantel is active against ileocecal tapeworm (A. perfoliata) when used at twice the recommended dose, although resistance has been reported.
Although there are apparently no pyrantel products approved for use in cattle, sheep, or goats, the drug is effective (as the tartrate) for the removal of the following parasites: Haemonchus spp., Ostertagia spp., Trichostrongylus spp., Nematodirus spp., Chabertia spp., Cooperia spp. and Oesophagostomum spp.
Pyrantel tartrate is indicated (labeled) for the removal or prevention of the following parasites in swine: large roundworms (Ascaris suum) and Oesophagostomum spp. The drug has activity against the swine stomach worm (Hyostrongylus rubidus).
Although not approved, pyrantel has been used in pet birds and llamas. See the Dosage section for more information.