Pyrantel comes as a capsule and a liquid to take by mouth. It usually is taken as a single dose for pinworm and roundworm infections. The dose usually is repeated after 2 weeks for pinworm infections. For hookworm infections, pyrantel usually is taken once a day for 3 days. Pyrantel may be taken with food, juice, or milk or on an empty stomach.
pyrantel
Shake the liquid well to mix the medication evenly. Pyrantel may be mixed with milk or fruit juice. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take pyrantel exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Pyrantel pamoate acts as a depolarizing neuromuscular blocking agent, thereby causing sudden contraction, followed by paralysis, of the helminths. This has the result of causing the worm to "lose its grip" on the intestinal wall and be passed out of the system by natural process. Since Pyrantel is poorly absorbed by the host's intestine, the host is unaffected by the small dosage of medication used. Spastic (tetanic) paralyzing agents, in particular pyrantel pamoate, may induce complete intestinal obstruction in a heavy worm load.[8] This obstruction is usually in the form of a worm impaction and happens when a very small, but heavily parasitized animal is treated and tries to pass a large number of dislodged worms at once. Worms usually pass in normal stool or with diarrhea, straining, and occasional vomiting.
Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of pyrantel in the elderly with use in other age groups.
Certain drugs may interact with pyrantel pamoate including levamisole (Ripercol, Tramisol), morantel (Rumatel), and piperazine (Pipa-Tabs). Exposure to organophosphates (pesticides) while taking pyrantel pamoate should be avoided. It is important to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.
Special thanks to Professor Peter Smith for his precious advice on statisticalanalysis, and to Victoria Wright for her contribution to the field activities, aswell as the revision of the manuscript. We are grateful to the staff of theParasitology Department of the Public Health Laboratory Ivo de Carneri on PembaIsland whose dedication and enthusiasm made this study possible. We acknowledge thedonation of placebo and mebendazole by Pharmamed (Malta), and of pyrantel-oxantel byPfizer (Indonesia). This study was generously supported by the Parasitic and VectorControl, Division of Communicable Diseases, World Health Organization.
Pyrantel was initially described in 1965 by researchers from Pfizer who sought cyclic amidines with suitable pharmacokinetic properties (specifically, duration of action) for use as an anthelmintic drug. Pyrantel is mainly available in formulations for dogs and cats as the embonate salt, containing a 34.7% pyrantel base 14.
Pyrantel is available in various formulations for humans, dogs, and cats as the pamoate (US Pharmacopeia nomenclature) or embonate (European Pharmacopoeia nomenclature) salt, which contains 34.7% pyrantel base combined with pamoic acid 8. 14, 4.
By promoting the release of acetylcholine, inhibiting cholinesterase, and stimulating ganglionic neurons, pyrantel serves as a depolarizing neuromuscular blocking agent in helminths. This causes extensive depolarization of the helminth muscle membrane, resulting in tension to the helminth's muscles, leading to paralysis and release of their attachment to the host organism intestinal walls 8.
Pyrantel is administered orally.The poor solubility of the pamoate salt offers the advantage of reduced absorption from the gastrointestinal tract and allows the drug to reach and act against parasites in the large intestine. Metabolism of pyrantel is rapid 22. The absorbed drug is partly metabolized in the liver 20.
Pyrantel pamoate has been placed in pregnancy category C. This refers to the fact that animal studies have revealed adverse effects on the fetus (teratogenic/embryocidal, or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus 9.Data on the use of pyrantel pamoate in pregnant women are quite limited. In mass treatment programs for which the World Health Organization (WHO) has observed that the benefits of treatment outweigh the risks, WHO allows the use of pyrantel pamoate in the 2nd and 3rd trimesters of pregnancy, due to the fact that the effects of pyrantel on birth outcome are uncertain. The risk of treatment in pregnant women already known to have an infection needs to be balanced with the risk of disease progression if treatment were to be omitted 9. Individuals with liver disease are more susceptible to the toxicity in cases of pyrantel overexposure 9, 11.
There are no data regarding the presence of pyrantel in breast milk. Pyrantel is poorly absorbed from the GI tract; therefore, excretion into breast milk may be minimal. Some experts recommend that a single dose of pyrantel therapy may be given to breastfeeding women 8.
Pyrantel (pi ran' tel) is a pyrimidine derivative which is believed to act by depolarizing the neuromuscular junction of nematodes, resulting in their paralysis and expulsion in stool. The drug is poorly absorbed from the intestine and is usually effective in a single dose. Pyrantel is currently available in the United States over-the-counter as tablets of 720 mg (250 mg pyrantel base) and in a suspension of 144 mg/mL (50 mg pyrantel base/mL) under the brand name Antiminth or Pin-X. It is recommended for pinworm infection due to Enterobius vermicularis and Ascaris lumbricoides. The typical dose in both adults and children is 11 mg/kg (up to 1 g) as a single dose, which can be repeated in two weeks. Pyrantel is widely used in veterinary medicine. Side effects are uncommon, mild and transient and include nausea, gastrointestinal upset and headache.
If you have questions about an adverse reaction or possible overdose of pyrantel, immediately check the webPOISONCONTROL online tool or call Poison Control at 1-800-222-1222 for help 24 hours a day, every day.
The purposes of this study were to evaluate pyrantel pamoate administered orally at 20 mg/kg body weight for the removal of induced or natural infections of Ancylostoma tubaeformae and Toxocara cati in cats and to compare the efficacy of paste (40 mg base/g) and granule (80 mg base/g) formulations. Thirty cats of mixed breeding and various ages with natural and/or induced infections of A. tubaeformae and T. cati were assigned to one of three treatment groups: (1) non-medicated controls; (2) paste formulation at 20 mg base/kg; or (3) granule formulation at 20 mg base/kg. Infections were induced by feeding the cats on carcasses of infected mice. The study was conducted in replicates of at least one animal per treatment per replicate. The study parameters included clinical observations, physical examinations, faecal egg counts and the numbers, species and stages of worms recovered at necropsy. The paste formulation was 99.3% and 99.7% effective in reducing egg counts of Ancylostoma sp. and Toxocara sp. respectively. The granule formulation was 97.7% and 99.9% effective in reducing faecal egg counts of Ancylostoma sp. and Toxocara sp. respectively. When administered in paste form, pyrantel pamoate was 99.5% effective in removing adult Ancylostoma and 100.0% effective against adult Toxocara. The granule formulation was 97.9% effective against Ancylostoma and 100% effective against Toxocara. No toxic effects of either formulation of the drug were noted.
While anthelmintic resistance is now a widely recognized issue in the livestock industries, its existence within companion animal medicine has been rarely established conclusively. We undertook a placebo-controlled in vivo trial to measure the efficacy of pyrantel embonate against pooled isolates of the hookworm Ancylostoma caninum from Brisbane, Australia. A statistically significant fall in adult worm burden was observed among dogs in the pyrantel treatment group compared to the control dogs (178.0+/-24.5 versus 239.7+/-14.0; p=0.02), equating to an efficacy of just 25.7% (95% CI, 15.0-35.1%), as based upon reduction in mean worm burden. Analysis of faecal egg count trends through the course of the study revealed that egg counts rose in both control and pyrantel-treated dogs, with a greater rise observed in the latter group (11.6+/-8.3% versus 17.3+/-7.6%; p=0.04), despite the decrease in adult worm numbers in this group. Our results indicate that high-level anthelmintic resistance does occur in companion animal medicine, and highlight the need for greater vigilance and more judicious use of anthelmintics in small animal practice. They further indicate that the faecal egg count reduction test needs to be used with caution with this parasite.
Pyrantel is an anthelmintic which acts as an agonist of nicotinic receptors (AChRs) of nematodes and exerts its therapeutic effects by depolarizing their muscle membranes. Here we explore at the single-channel level the action of pyrantel at mammalian muscle AChR. AChR currents are elicited by pyrantel. However, openings do not appear in clearly identifiable clusters over a range of pyrantel concentrations (1-300 microM). The mean open time decreases as a function of concentration, indicating an additional open-channel block. Single-channel recordings in the presence of high ACh concentrations and pyrantel demonstrate that the anthelmintic acts as a high-affinity open-channel blocker. When analyzed in terms of a sequential blocking scheme, the calculated forward rate constant for the blocking process is 8x10(7) M(-1) x s(-1), the apparent dissociation constant is 8 microM at a membrane potential of -70 mV and the process is voltage dependent. Pyrantel displaces alpha-bungarotoxin binding but the concentration dependence of equilibrium binding is shifted towards higher concentrations with respect to that of ACh binding. Thus, by acting at the binding site pyrantel activates mammalian AChRs with low efficacy, and by sterical blockade of the pore, the activated channels are then rapidly inhibited. 2ff7e9595c
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