Фебантел инструкция по применению в ветеринарии

Indications and clinical uses

Febantel is indicated in the control and treatment of larvae and adult stages of intestinal nematodes. In horses, it is used for removal of large strongyles (Strongylus vulgaris, S. edentatus, S. equinus), ascarids (Parascaris equorum, sexually mature and immature), pinworms (Oxyuris equi, adult and fourth-stage larvae), and the various small strongyles.

In dogs and cats, it is used for treatment of hookworms (Ancylostoma caninum and Uncinaria stenocephala), ascarids (Toxocara canis and Toxascaris leonina), and whipworms (Trichuris vulpis). In dogs, it is used in combination with praziquantel for treatment of hookworms (A. caninum and U. stenocephala), whipworms (T. vulpis), ascarids (T. canis and T. leonina), and tapeworms (Dipylidium caninum and Taenia pisiformis).

In cats, it is used in combination with praziquantel for removal of hookworms (A. tubaeforme), ascarids (Toxocara cati), and tapeworms (D. caninum and Taenia taeniaeformis).

Febantel has been used with pyrantel (Drontal Plus) for treatment of Giardia.

Clinical Application

Fenbendazole and febantel are prescribed frequently for the target helminths as discussed (see Tables 37-1 and 37-2). However, neither compound is effective for the treatment of Dipylidium caninum or Echinococcus spp. infections. Febantel is combined with praziquantel (see “Isoquinolones” section), which effectively treats the other tapeworms and pyrantel (see “Tetrahydropyridimines” section), which increases its activity against hookworms and roundworms (Drontal Plus, Bayer Animal Health). Benzimidazoles also treat Trichuris vulpis infections, which is an advantage over some of the drugs in other classes with anthelmintic activity.

Fenbendazole or febantel are also commonly prescribed to dogs or cats with small bowel diarrhea for potential activity against Giardia spp. (see Chapter 57).^14-17 Fenbendazole is one of the anthelmintics that is believed to have activity against the trematodes that can be associated with gastrointestinal disease (Alaria spp., Nanophyetus salmincola, Heterobilharzia americana, Platynosomum fastosum).¹⁸ However, optimal protocols have not yet been established and fenbendazole is not labeled for this use.

Febantel

[[2-[(methoxyacetyl)amino]-4-(phenyl-thio) phenyl]carbonimidoyl]biscarbamic acid dimethyl ester).

4.2.2 Pyrantel Embonate

Pyrantel embonate (European Pharmacopoeia) is considered to be synonymous with pyrantel pamoate (US Pharmacopeia). For some anthelmintics approved in New Zealand, pyrantel pamoate is listed in the registration details whereas the package label identifies the same chemical as pyrantel embonate. The label indications of these two pyrantel salts are virtually interchangeable at the same concentrations and dosages. Given this common identity, the only examples presented in this section are unique formulations or combination anthelmintics for which no comparable product containing pyrantel pamoate could be identified.

Benzimidazoles (Fenbendazole, Flubendazole, Febantel, Oxfendazole, and Albendazole)

Fenbendazole is a widely used antiparasitic drug of dogs. Febantel is a drug that is metabolized to fenbendazole. Fenbendazole is effective against nematodes, including the migrating stages of canine roundworm, as well as some cestodes. If a bitch is given fenbendazole on day 40 of the pregnancy and the treatment is continued daily until the puppies are 14 days old, puppies have 89% less roundworms than puppies of untreated bitches. This regimen, however, is not for routine use in all pregnant bitches. Fenbendazole is often the primary treatment of Giardia infections in dogs. Benzimidazoles interfere with the organization of microtubules inside the parasite cell and inhibit the elimination of cellular waste and absorption of nutrients. Parasite cells become emaciated quite rapidly and the parasite dies. Benzimidazoles are well tolerated and even multiple label doses rarely cause adverse effects. Albendazole has been reported to cause bone marrow suppression in dogs, and it should be used with caution. Resistance has developed against the drugs of the benzimidazole group among equine, ovine and caprine nematodes, but resistance has not been widely reported in worms parasitizing dogs yet.

Treatment

Drugs effective for treatment of Trichuris spp. infections include fenbendazole and febantel. The latter drug is partially metabolized to fenbendazole and oxibendazole. Regular use of milbemycin oxime for heartworm prevention is also effective for treatment and prevention of T. vulpis infection.¹⁶ Immature worms are less susceptible to drug treatment and it takes approximately 3 months for larval stages to mature to egg-laying adults. Therefore, treatment should be repeated in 3 weeks and again in 3 months. Whipworm ova survive for prolonged periods of time in the environment and dogs housed in areas that are difficult to decontaminate (e.g., on dirt) may need to be retreated every 2 to 3 months. When possible, feces should be collected and removed.

Control

Treatment of pigeons suffering from ascaridiosis or capillariosis is by a single oral dose of levamisole, febantel, fenbendazole or cambendazole (Devriese 1986, Baert et al 1993). In heavily infested pigeons, treatment must be repeated after 10 days. Pigeons should be left unfed during levamisole administration, since this product induces vomiting. Benzimidazole anthelmintics should not be used during moulting, since they can induce feather abnormalities.

Cestodes and trematodes in pigeons can be controlled by oral treatment with praziquantel (Devriese 1986) and by eliminating contact with the intermediate hosts.

Reinfection of pigeons must be avoided by taking hygienic measures such as thorough cleaning of the loft. Embryonation of the eggs will be arrested in a dry environment without organic materials. Disinfectants are not effective against worm eggs.

Treatment and Prevention

Treatment

Use of many drugs for the treatment of canine or feline giardiasis was extrapolated from use in humans.⁷⁰ Because dog and cat Giardia spp. have been difficult to grow in culture, there are minimal data on antimicrobial sensitivities. It is likely that sensitivities vary amongst different isolates and it is currently impossible to predict which anti-Giardia drug will be effective in an individual case. Although there have been multiple drugs used for the treatment of giardiasis in dogs and cats, there are few studies that utilized dose titrations and evaluation of drugs in experimentally infected animals. In most studies, fecal samples were only assessed for short periods of time after treatment and neither was immune suppression induced nor necropsy performed to evaluate whether infection was eliminated or merely suppressed. Infection with Giardia does not appear to cause permanent immunity and so reinfection can occur, a finding that also hampers assessment of treatment studies.

The primary goal of Giardia treatment is to stop diarrhea. Because healthy pets are not considered significant health risks to immunocompetent people, elimination of infection (which is difficult) is a secondary goal. Treatment options currently available or used historically include metronidazole, tinidazole, ipronidazole, ronidazole, fenbendazole, albendazole, pyrantel/praziquantel/febantel, quinacrine, furazolidone, and nitazoxanide (Table 57-6).^70-83

Care should be taken when using metronidazole or ronidazole as central nervous system (CNS) toxicity can occur.^84-86 Because albendazole is associated with bone marrow suppression, many clinicians use fenbendazole or febantel when that class of drugs is chosen.⁸⁷

If clinical findings suggest concurrent C. perfringens overgrowth, use of metronidazole may be indicated as this drug is an antibiotic with activity against Clostridium spp. If there are clinical findings that suggest concurrent infection with a nematode, fenbendazole or febantel are indicated. Many clinicians currently use fenbendazole once daily for 3 to 5 days as initial therapy. Some clinicians currently recommend the combination of metronidazole and fenbendazole (www.capcvet.org). Others only resort to combination therapy if there is evidence of a persistent infection that is not cleared by monotherapy. If the first drug fails to control diarrhea and the organism is still detected in feces, a second drug from an alternate class is indicated. The addition of fiber to the diet may help control clinical signs of giardiasis in some animals by helping to suppress bacterial overgrowth or by inhibiting organismal attachment to intestinal microvilli. Immunotherapy with the Giardia vaccine has aided in eliminating cyst shedding and diarrhea in some infected dogs.⁸⁸ However, in a controlled study in 16 experimentally infected cats, vaccination as immunotherapy was ineffective with one strain of Giardia.⁸⁹ In addition, both commercial products have been discontinued. Probiotic administration has been promoted as potentially beneficial in the control of giardiasis. In one study, dogs treated with silymarin and metronidazole had superior clinical responses to dogs treated with metronidazole alone.⁹⁰ However, in another study, administration of a commercially available probiotic (Forta-Flora, Nestle Purina PetCare, St. Louis, MO) did not affect the outcome of Giardia infection.⁹¹ In one study, bathing the dog on the last day of treatment was a beneficial adjunct therapy.⁷⁷ In dogs and cats with persistent diarrhea and Giardia spp. infection, a more extensive workup to attempt to diagnose other underlying diseases is indicated if several therapeutic trials fail. Common underlying disorders include cryptosporidiosis, T. foetus in cats, IBD, bacterial overgrowth, exocrine pancreatic insufficiency, and immunodeficiencies.

Treatment

Two commonly available drugs are used most frequently to treat infections with G. duodenalis (see Table 23-20). Fenbendazole may be effective and can be used in pregnant queens²⁸ and in cats co-infected with roundworms, hookworms, and Taenia spp. tapeworms.³⁹ However, in one small study, only four of eight cats infected with both G. duodenalis and Cryptosporidium felis stopped shedding Giardia permanently after receiving fenbendazole.²⁹ Febantel, in the combination product Drontal Plus (Bayer Animal Health), is converted to fenbendazole. When six experimentally infected cats received 56.5 mg/kg of febantel q24h PO for 5 days, four of them stopped shedding G. duodenalis cysts.³⁹

Metronidazole has been the traditional drug used to treat G. duodenalis in pets.²⁸ The drug is also useful for treating concurrent small intestinal bacterial overgrowth and clostridial infections.³⁹ The administration of metronidazole may eliminate shedding in 67% of cats.²⁶ Neurologic side effects may occur at the dose recommended for treatment of Giardia (see above, Therapeutics for Vomiting and Diarrhea). The use of a Giardia vaccine was ineffective in clearing infection by itself.⁴⁴

The combination of fenbendazole and metronidazole has been suggested as the initial treatment of choice for G. duodenalis infections.³⁹ Although controlled studies are lacking, they may work synergistically by acting on two different targets within the parasite.²⁸ Febantel would be expected to have the same synergism with metronidazole.

Drug therapy may not be necessary in cats without diarrhea that are infected with G. duodenalis,³⁷ because it is uncommon for a cat to carry the assemblages required to infect humans. The veterinarian may be obligated to treat a healthy cat if the owner wants to treat, the owner is immunocompromised, or the goal is eradication of an infection from a multicat home or prevention of parasite transmission to Giardia-naïve cats is attempted.²⁸

What may appear to be treatment failure is more likely to be re-infection. In addition to drug therapy, steps should be taken to prevent re-infection. All cats with diarrhea positive for G. duodenalis should be treated along with their housemates.³⁷ Sanitation is imperative in the fight against re-infection and transmission of G. duodenalis. Dispose of old litter pans and scoops and use disposable litter boxes during treatment. When the infection is eliminated, not just controlled, new litter boxes and scoops may be purchased. Bathe all cats during treatment to remove cysts from the hair coat. Since Giardia spp. cysts are susceptible to desiccation,²⁸ blow-dry all cats using a warm air blower, paying particular attention to the perineal area. Disinfect bowls, housing, and other utensils with bleach.²⁸

In addition to antiprotozoal drugs and sanitation, supportive care may become necessary. Probiotics and a highly digestible, bland diet may be offered to cats with small bowel diarrhea, while a high-fiber diet may be useful for those few cats with large bowel diarrhea.³⁹ Where required, hydration and electrolyte imbalances must be corrected and antiemetics used to control vomiting.

Therapy can be evaluated by retesting feces with a zinc sulfate centrifugal flotation examination 1 to 3 days after the end of treatment and again 3 weeks later. A positive test immediately posttreatment is most likely because of therapeutic failure. If the cat is negative immediately after treatment ends, but is positive 3 weeks later, re-infection is likely.²⁸ Since the fecal antigen test may remain positive long after the infection is eradicated, this test is inappropriate for evaluating therapy.^28,39

Re-treatment of fecal flotation-positive, recovered cats may be handled in a manner similar to the positive healthy cat mentioned above.²⁸ Cats with diarrhea that continue to shed cysts may be re-treated for G. duodenalis infection along with dietary modification and empirical treatment for other common intestinal parasites. However, serious consideration should be given to investigation into other potential causes of diarrhea.²⁸