Fenbendazol
Fenbendazole
Methyl [5-(phenylthio)-1H-benzimidazol-2-yl]carbamate
También conocido como: Panacur · Safe-Guard · Granofen · Wormazole · Hoe-881V · Fenbendazolum
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
Evidencia de dosis v13 auditada
Evidencia estructurada para el cálculoEncephalitozoon cuniculi infection after diagnostic risk-benefit discussion
- q24h · 30d
Contexto clínico obligatorio (9)
- Infections marked by ocular, CNS, and renal disease
- Otitis interna and/or media
- Most common cause of vestibular signs must exclude first
- CNS infections (toxoplasmosis, abscess), neoplasia, trauma
- Many North American and European rabbits will be positive, indicative of prior (in utero) exposure and not necessarily active disease
- Definitive diagnosis based on organism (obligate intracellular microsporidian parasite) identification in affected tissues, generally postmortem
- Head CT/MRI is considered for excluding bulla disease, abscess, neoplasia
- Positive serology and response to treatment supports presumed diagnosis, but risk/benefit discussion required prior to initiation
- Risk of bone marrow suppression/aplastic anemia/pancytopenia with therapy must be considered/discussed prior to therapy
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
El fenbendazol es un antihelmíntico benzimidazol de amplio espectro y alta eficacia, ampliamente utilizado en medicina veterinaria en múltiples especies.
Características clínicas clave:
- Eficacia contra nematodos: Altamente eficaz contra ascáridos gastrointestinales, anquilostomas y tricúridos.
- Eficacia contra cestodos: Eficaz contra tenias del género Taenia, pero no es eficaz contra la tenia común de la pulga (Dipylidium caninum).
- Eficacia contra protozoos: Considerado un tratamiento de primera línea para infecciones por Giardia en perros y gatos.
- Parásitos respiratorios: Utilizado frecuentemente para diversas infecciones por gusanos pulmonares (p. ej., Aelurostrongylus, Capillaria, Paragonimus).
Perla clínica: El fenbendazol tiene un margen de seguridad excepcionalmente amplio y se considera el fármaco de elección para tratar infecciones parasitarias, incluida la Giardia, en animales gestantes.
Mecanismo de acción
Fenbendazole is a time-dependent antiparasitic agent, which is why multi-day dosing is typically required in small animals.
- Primary Mechanism: It selectively binds to parasite β-tubulin → prevents tubulin polymerization → inhibits microtubule formation. This disrupts essential intracellular transport mechanisms within the parasite.
- Secondary Mechanism: At higher concentrations, it disrupts metabolic pathways by inhibiting key enzymes such as fumarate reductase and malate dehydrogenase → depletes ATP/energy reserves → parasite death.
Seguridad y advertencias
Contraindicaciones
- Not FDA-approved for use in horses intended for food purposes
Efectos adversos
- Hypersensitivity reactions (secondary to antigen release by dying parasites)
- Salivation (infrequent)
- Vomiting (infrequent)
- Diarrhea (infrequent)
- Pancytopenia (rarely reported in dogs)
- Bone marrow hypoplasia (rarely reported in dogs)
Precauciones
Important: Single doses are generally not effective in dogs and cats; treatment must continue for at least 3 consecutive days.
- Hypersensitivity: Reactions may occur secondary to antigen release by dying parasites, particularly in animals with high parasite burdens.
- Food Animal Withdrawal: Observe appropriate slaughter withdrawal times for cattle and swine based on the specific product used.
Interacciones farmacológicas
Abortions in cattle and death in sheep have been reported after concurrent use
Monitorización
- Fecal examinations to confirm parasite clearance
- Monitor for hypersensitivity reactions if treating heavy parasite burdens
- Fecal examination for parasite clearance
- Complete blood count (CBC) if bone marrow hypoplasia is suspected
Farmacocinética
Absorción
Marginally absorbed after oral administration. The amount absorbed from the gut is associated with the solubility of the drug, not the dose given. Bioavailability is significantly increased in dogs when administered with food (fat content does not alter this).
Distribución
Reaches systemic circulation sufficiently to treat migrating larvae and lungworms, though specific distribution parameters are not detailed.
Metabolismo
Absorbed fenbendazole is metabolized to the active compound oxfendazole (sulfoxide) and the sulfone.
Eliminación
In sheep, cattle, and pigs, 44-50% of a dose is excreted unchanged in the feces, and <1% in the urine.
Sobredosis
Fenbendazole is exceptionally well tolerated, even at doses up to 100X the recommended dose.
- The LD50 in laboratory animals exceeds 10 grams/kg when administered orally.
- It is highly unlikely that an acute overdosage would lead to any significant clinical signs.
Productos disponibles
Formulaciones
- Granules (22.2%)
- Paste (10%)
- Type B Medicated Feed (1.8%, 0.96%)
- Type C Medicated Feed (0.50%, 35% Salt Free-choice)
- Pellets (0.5%, 1.96%)
- Premix 20% Type A
- Chewable Tablets (Combination with Ivermectin and Praziquantel)
- 222 mg/g oral granules (22%)
- 440 mg/g oral granules (44%)
- 880 mg/g oral granules (88%)
- 25 mg/ml oral suspension (2.5%)
- 100 mg/ml oral suspension (10%)
- 187.5 mg/g oral paste (18.75%)
Veterinario
- Fenbendazole Granules: 222 mg/gram (22.2%)
- Fenbendazole Suspension: 100 mg/mL (10%)
- Fenbendazole Paste: 100 mg/gram (10%)
- Fenbendazole Type B Medicated Feed (1.8%, 0.96%)
- Fenbendazole Type C Medicated Feed (0.50%, 35% Salt Free-choice)
- Fenbendazole Pellets (0.5%, 1.96%)
- Fenbendazole Premix 20% Type A (200 mg/gram)
- Combination Products: Fenbendazole/Ivermectin/Praziquantel Chewable Tablets (Panacur Plus Soft Chews)
- Granofen
- Wormazole
Estado regulador
Authorized proprietary products available.
Available as AVM-GSL (General Sales List) and NFA-VPS (Non-Food Animal - Veterinarian, Pharmacist, SQP).
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Fenbendazole products should be stored at room temperature.
Información para el cliente
Importante: En perros, administre siempre este medicamento con comida para mejorar significativamente su absorción y eficacia.
- Dosificación de varios días: A diferencia de algunos desparasitantes de dosis única, el fenbendazol generalmente requiere de 3 a 5 días consecutivos de tratamiento para ser efectivo. No omita dosis.
- Seguridad: Es muy seguro, pero ocasionalmente las mascotas pueden experimentar vómitos leves, salivación o diarrea.
- Qué esperar: Es posible que vea gusanos muertos en las heces de su mascota después del tratamiento; esto es normal.
- Tratamiento para Giardia: Si está tratando una infección por Giardia, asegúrese también de bañar a su mascota (especialmente la parte trasera) y limpiar a fondo su entorno para prevenir la reinfección.
La referencia de medicamentos de VetSheet está destinada a profesionales veterinarios autorizados como ayuda para la toma de decisiones clínicas, no como sustituto del criterio profesional ni del prospecto actual del fabricante.