FEBANTEL
Chemistry - A phenylguanidine anthelmintic, febantel occurs as a colorless powder. It is insolublein water and alcohol. Structurally, febantel is related to the benzimidazoles. As febantel is at leastpartially metabolized to fenbendazole and oxibendazole in vivo, it is sometimes categorized as aprobenzimidazole agent.
Partially used febantel (Rintal®) syringes may be stored for up to one year if capped tightly andexpiration date is not exceeded. When mixed extemporaneously with trichlorfon (Combot®), itshould be stored tightly sealed and used within 6 days if kept at room temperature and within 2months if refrigerated. Mix well before administering.
Febantel (in combination with praziquantel¯Vercom®) is indicated (labeled) for the followingintestinal parasites in dogs and puppies: hookworms (Ancylostoma caninum), roundworms(Toxocara canis), whipworms (Trichuris vulpus) and tapeworms (Dipylidium caninum & Taeniapisiformis).
Febantel (in combination with praziquantel¯Vercom®) is indicated (labeled) for the followingintestinal parasites in cats and kittens: hookworms (Ancylostoma tubaeforme), roundworms(Toxocara canti) and tapeworms (Dipylidium caninum & Taenia taeniaeformis).
Although not approved for use in cattle or sheep, febantel has greater than 85% efficacy againstthe following helminths in those species: Abomasal nematodes, small intestinal nematodes, largeintestinal nematodes (Oesophogostomum spp.), lungworms and trematodes (F. hepatica¯ 4 weekto 15 week stages; not in sheep).
Contraindications/Precautions - When used alone in horses, the manufacturer lists no contraindications to the use of the drug. It is considered to be safe in breeding stallions and pregnant mares. The combination product (Combotel®) is labeled as being contraindicated in horses "...suffering from colic, diarrhea, constipation, or infectious disease until such conditions have been corrected."
The combination product (Vercom®) is contraindicated in pregnant small animals.
Adverse effects in horses with the combination product Combotel®, include mouth irritation withresultant salivation, occasional diarrhea and colic. Adverse effects are more likely to occur if givenon an empty stomach or if feed is withheld prior to dosing.
In dogs and cats, Vercom® (febantel & praziquantel) is unlikely to cause serious adverse effects atusual doses. Dogs may exhibit salivation, anorexia, emesis or gagging, and diarrhea or soft stools.
Incidence of these effects was less than 3% of dogs treated in clinical trials. Cats may show signs(less than 10% incidence) of salivation, vomiting, depression and rejection of the paste. Theseeffects are described as mild and self-limiting.
Overdosage/Toxicity - In horses, febantel has a reported 40X margin of safety after a single oral dose. Slightly decreased red blood cel counts, hemoglobin and hematocrit may be noted for 3 weeks after this dosage. Repeated doses of 8X recommended resulted only in a self-limiting diarrhea.
While, in horses there is a considerable safety factor for febantel, there is much less so fortrichlorfon (in Combotel®). For more information on the toxicity for this compound (trichlorfon)refer to its monograph found later in this section.
The LD50 in dogs is greater than 10 g/kg of febantel. When administered at 15X recommendeddose to mature dogs and cats, or 10X recommended dose to puppies or kittens for 6 days, transientsalivation, diarrhea, vomiting and anorexia were noted. In dogs receiving 5 or 10 mg/kg PO for 90days, testicular and prostatic hypoplasia were noted.
Drug Interactions, Drug/Laboratory Interactions - None reported.
Storage, Stability, Compatibility
Febantel (alone) should be stored at room temperature.Partially used febantel (Rintal®) syringes may be stored for up to one year if capped tightly andexpiration date is not exceeded. When mixed extemporaneously with trichlorfon (Combot®), itshould be stored tightly sealed and used within 6 days if kept at room temperature and within 2months if refrigerated. Mix well before administering.
Pharmacology - FEBANTEL
The mode of action of this agent is thought to be via inhibition of fumarate reductase in the worm, thereby blocking glucose uptake. The majority of the activity is believed to be derived from the active metabolites, fenbendazole and oxfendazole.Uses, Indications
Febantel paste and oral (tube) suspension is indicated (labeled) for the treatment of large and small strongyles (Strongulus vulgaris, S. edentatus, S. equinus), ascarids (P. equorum¯adult and sexually immature forms), and pinworms (Oxyuris equi¯adult and 4th stagelarva) in horses. In combination with trichlorfon (Combotel®), it is indicated (labeled) for theremoval of the mouth and stomach stages of bots (Gastrophilus intestinalis, G. nasalis).Febantel (in combination with praziquantel¯Vercom®) is indicated (labeled) for the followingintestinal parasites in dogs and puppies: hookworms (Ancylostoma caninum), roundworms(Toxocara canis), whipworms (Trichuris vulpus) and tapeworms (Dipylidium caninum & Taeniapisiformis).
Febantel (in combination with praziquantel¯Vercom®) is indicated (labeled) for the followingintestinal parasites in cats and kittens: hookworms (Ancylostoma tubaeforme), roundworms(Toxocara canti) and tapeworms (Dipylidium caninum & Taenia taeniaeformis).
Although not approved for use in cattle or sheep, febantel has greater than 85% efficacy againstthe following helminths in those species: Abomasal nematodes, small intestinal nematodes, largeintestinal nematodes (Oesophogostomum spp.), lungworms and trematodes (F. hepatica¯ 4 weekto 15 week stages; not in sheep).
Pharmacokinetics - FEBANTEL
In the horse, febantel is apparently readily absorbed from the GI tract and israpidly metabolized to fenbendazole-sulphone, fenbendazole and oxibendazole. Febantel is alsoabsorbed from the intestine in cat le and sheep. Sheep apparently absorb and metabolize the drugfaster than do cattle. Maximum plasma concentrations occur 6-12 hours after dosing in sheep and12-24 hours in cattle.Contraindications/Precautions - When used alone in horses, the manufacturer lists no contraindications to the use of the drug. It is considered to be safe in breeding stallions and pregnant mares. The combination product (Combotel®) is labeled as being contraindicated in horses "...suffering from colic, diarrhea, constipation, or infectious disease until such conditions have been corrected."
The combination product (Vercom®) is contraindicated in pregnant small animals.
Adverse Effects, Warnings
When used at recommended dosages in horses, adverse reactions areunlikely to occur. Anaphylaxis is listed as a possible reaction, but case reports documenting thiswere not found in the literature. At very high doses (8 times labeled), a self-limiting diarrhea hasbeen described.Adverse effects in horses with the combination product Combotel®, include mouth irritation withresultant salivation, occasional diarrhea and colic. Adverse effects are more likely to occur if givenon an empty stomach or if feed is withheld prior to dosing.
In dogs and cats, Vercom® (febantel & praziquantel) is unlikely to cause serious adverse effects atusual doses. Dogs may exhibit salivation, anorexia, emesis or gagging, and diarrhea or soft stools.
Incidence of these effects was less than 3% of dogs treated in clinical trials. Cats may show signs(less than 10% incidence) of salivation, vomiting, depression and rejection of the paste. Theseeffects are described as mild and self-limiting.
Overdosage/Toxicity - In horses, febantel has a reported 40X margin of safety after a single oral dose. Slightly decreased red blood cel counts, hemoglobin and hematocrit may be noted for 3 weeks after this dosage. Repeated doses of 8X recommended resulted only in a self-limiting diarrhea.
While, in horses there is a considerable safety factor for febantel, there is much less so fortrichlorfon (in Combotel®). For more information on the toxicity for this compound (trichlorfon)refer to its monograph found later in this section.
The LD50 in dogs is greater than 10 g/kg of febantel. When administered at 15X recommendeddose to mature dogs and cats, or 10X recommended dose to puppies or kittens for 6 days, transientsalivation, diarrhea, vomiting and anorexia were noted. In dogs receiving 5 or 10 mg/kg PO for 90days, testicular and prostatic hypoplasia were noted.
Drug Interactions, Drug/Laboratory Interactions - None reported.