Fenbendazole is a white or off-white powder, odorless and tasteless. This product is soluble in dimethyl sulfoxide, slightly soluble in methanol, insoluble in water, and soluble in glacial acetic acid. Fenbendazole is a benzimidazole anthelmintic. It not only has high anthelmintic activity against adults and larvae of gastrointestinal nematodes, but also has good effects on Dictychocerciata, Fasciola and tapeworms, and has a strong killing effect. Egg effect.
The detailed pharmacological effects of fenbendazole are:
(1) Adults and larvae of Haemonchus ovis, Osteria, Trichostrongylus, Cooperia elegans, Leptocollis nematode, Yangia nematode, Chabot nematode, Esophagostomia nematode, Trichocephalus elegans and Dictychocerpha elegans All have excellent insect repellent effects. In addition, it can inhibit the egg laying of most gastrointestinal nematodes. The application of high-limit dosage is also effective against expanded Monitz tapeworm and Monitz tapeworm burnetii in sheep. However, large doses must be applied continuously to be effective against flukes. For example, if 20 mg/kg is used for 5 days, and 15 mg/kg is used for 6 days, double-chambered flukes and Fasciola hepatica can be driven away.
(2) The deworming spectrum of cattle to cattle is roughly similar to that of sheep. For example, it is highly effective against adults and larvae of Haemonchus nematodes, Oerstedia nematodes, Trichostrongylus elegans, Yangostomia nematodes, Leptocollis nematodes, Cooper nematodes, Esophagostomia nematodes, and Dictychocerca viviparous nematodes. However, for Fasciola hepatica and Pterostridium hepatica, a dose of 7.5 to 10 mg/kg needs to be used for 6 days to be effective. Fenbendazole also inhibits egg-laying effects on nematodes. After one dose, no eggs will be excreted in the feces 22 to 36 hours later.
(3) Horses are highly effective against Paracaris equi, adults and larvae of A. equi, Prevotella viviparous, Roundworm vulgaris, Roundworm toothless, Roundworm equi, and Roundworm small. However, it is ineffective against softworms, gymnocephalus tapeworms, Strongyloides strongyloides and strongyloides larvae that have transferred to the mesentery.
(4) Pigs Although some people believe that one-time administration of fenbendazole is effective against adults and larvae of Strongyloides rubrum, roundworms, and esophageal stoma nematodes, the United States currently recommends continuous administration to enhance the anthelmintic effect. For example, for Trichocephalus suis, if 15 mg/kg is applied once, the efficacy is only 65%, while if 3 mg/kg is used for 6 days, the anthelmintic effect exceeds 99%. Since the dosage is 3mg per kilogram of body weight, it should be used for 3 days in a row. The elimination rate for Ascaris suum, Esophagostomum nematode, Red Strongyloides suis, Opisthorstrongyloides suis (effective dose for one dose is 25mg/kg), and even the elimination rate of Crowntail worm (porcine kidney worm) is almost 100%. In addition, for some Insect larvae are also quite effective and are currently widely used abroad.
(5) For dogs and cats, the daily dose of 50 mg/kg for 3 days is highly effective against hookworms, roundworms, and Trichocephalus in dogs and cats. 50 mg/kg daily dosage for 5 days is the best deworming plan for cat lungworm (Aelurostrongylus abstrusus); 3 days for cat stomach worm (Ollulanus) are the best deworming options.
(6) Poultry is effective against poultry gastrointestinal and respiratory nematodes. Used at a daily dose of 8mg/kg for 6 days, it is highly effective against roundworms, capillaries and tapeworms. The effective dose for turkey roundworms is 350 mg/kg, but if fed at a feed concentration of 45 mg/kg for 6 days, turkey roundworms, heterospermia and closed capillaries will all be eliminated. The best deworming program for pheasants, partridges, grouse, geese, and ducks is a feed concentration of 60 mg/kg for 6 days. Domestic pigeons naturally infected with Capillaris elegans and Ascaris lumbricoides are fed mixed feeding with 100 mg/kg for 3 to 4 days, and the effective rate is almost 100%.
(7) Wild animals Since fenbendazole has a safe and reliable deworming effect on various wild animals in zoos, the US FDA has approved a special preparation. A brief introduction is as follows: Toxocara felis, Toxocara leonata, Ancylostoma, and tapeworms in lions, tigers, and leopards; Toxocara lionis, tapeworms, Baylisascaris transtuga, and Luojishanda in bears Protostrongylus elegans in horned sheep can be taken orally at a dose of 10 mg per kilogram of body weight for 3 days. For wild ruminants, Haemonchus elegans, Trichostrongylus elegans, Trichostrongylus elegans, Trichocystis elegans, wild boar Ascaris suum, Dentoesophagostomum nematode, and Coryodonta dentata, the daily dose is 2.5 mg and 3 mg/kg respectively. , used for 3 consecutive days. Other data confirm that for various raptors that are seriously infected with avian roundworms, sawnose nematodes, capillary nematodes and flukes, feeding them at 25mg/kg for 3 days can almost eliminate the above-mentioned parasites.
(8) Kill eggs Fenbendazole has a killing effect on ruminant Trichostrongylus nematodes, strongyloidia suis, roundworms, as well as hookworms and whipworm eggs in humans and dogs.
Pharmacodynamics Fenbendazole is a new benzimidazole anthelmintic with broad spectrum, high efficiency and low toxicity medicine. It not only has high anthelmintic activity against adults and larvae of animal gastrointestinal nematodes, but also has good effects on Dictychocerca nematodes, Aphrodisiac flukes, Fasciolopsis and tapeworms. Fenbendazole is not only used in various animals abroad, but also has special preparations for wild animals.
Pharmacokinetics Due to the low solubility of fenbendazole, it is rarely absorbed when administered orally to animals, such as sheep and cattle. , due to poor absorption after oral administration by pigs, approximately 44% to 50% of the prototype drug is excreted in feces, while less than 1% is excreted in urine. After oral administration in piglets, the blood drug reaches the peak value in 8 to 12 hours, with a half-life of 10 hours, while in cattle and sheep it takes 24 to 30 hours to reach the peak value, t1/225-30 hours, and in rabbits, t1/2 is 15 hours; while in rats and mice, it takes 24 to 30 hours to reach the peak value.�. Dogs can excrete it from the body 3 to 7 days after taking the medicine.
After absorption, fenbendazole mostly forms metabolites in animals, such as ruminants, mainly in Hydroxylation occurs on the benzene ring, and some also undergo deethoxycarbonylation. A large number of metabolites are also formed in pigs. Some studies have even confirmed that these metabolites in sheep can be recirculated in the liver and fu organs after being secreted by bile.
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