Fluorouracilo
Fluorouracil
5-fluorouracil
También conocido como: Adrucil · Efudix · 5-FU · 5-fluorouracil · fluorouracilo · fluorouracilum · NSC-19893 · Ro-2-9757 · WR-69596
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
Esta dosis se basa en la superficie corporal (mg/m²). Convierta el peso en superficie corporal antes de administrarla.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Dosis por especie
🌎 NA — North America🌍 EU — Europe
Perros
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| Canine mammary carcinoma (in combination with doxorubicin and cyclophosphamide-FAC protocol), dermal squamous cell carcinoma and GI tract tumors | 150 mg/m2 IV weekly, or 5-10 mg/kg IV weekly | IV | weekly | — | 🌎 NA |
| Systemic carcinomas | 150 mg/m2 | IV | once weekly OR once every 3 weeks when combined with carboplatin | 6 weeks (if used weekly) | 🌍 EU |
| Basal cell and squamous cell carcinoma | Apply to affected area | topical | q24h | As directed by oncologist | 🌍 EU |
- Systemic carcinomas: Reduce dose by half in patients with liver, renal, or bone marrow impairment.
- Basal cell and squamous cell carcinoma: Wear gloves when applying. Prevent the dog from licking the area.
Gatos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| ALL | CONTRAINDICATED | ALL | — | — | 🌎 NA |
| All indications | DO NOT USE | PO/IM/IV/SC/topical | null | null | 🌍 EU |
- ALL: Do NOT use in any form on cats
- All indications: Strictly contraindicated. Causes potentially fatal neurotoxicity.
Caballos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| Intratumoral injection with epinephrine into certain skin neoplasms (squamous cell carcinoma, melanoma, sarcoid) | 0.3 mL of 1:1000 epinephrine is added to each mL of 5-FU solution up to a maximum of 3 mL of epinephrine per total volume of 5-FU injected. | Intratumoral | — | — | 🌎 NA |
- Intratumoral injection with epinephrine into certain skin neoplasms (squamous cell carcinoma, melanoma, sarcoid): Epinephrine may result in white hair growth and can cause transient excitation, tachycardia, and shaking if absorbed systemically in sufficient quantities.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
El fluorouracilo (5-FU) es un agente antineoplásico análogo de la pirimidina utilizado en medicina veterinaria para tratar tipos específicos de cáncer.
- Perros: Se utiliza por vía sistémica para el carcinoma mamario (a menudo como parte del protocolo FAC junto con doxorrubicina y ciclofosfamida), carcinoma de células escamosas dérmico y tumores del tracto gastrointestinal.
- Caballos: Se utiliza por vía tópica o mediante inyección intralesional (a menudo combinado con epinefrina) para tratar neoplasias cutáneas como el carcinoma de células escamosas, melanoma y sarcoides equinos.
DIFERENCIA CRÍTICA ENTRE ESPECIES: El 5-FU está estrictamente contraindicado en gatos. Los gatos carecen de las vías metabólicas necesarias para procesar el fármaco de forma segura, lo que provoca una neurotoxicidad grave, de progresión rápida y frecuentemente mortal, incluso con dosis microscópicas (por ejemplo, ingestión accidental de cremas tópicas de uso humano).
Mecanismo de acción
Fluorouracil is a prodrug that acts as a cell-cycle phase-specific (S-phase) antimetabolite. It enters the cell and is converted into two primary active metabolites:
- FUMP (fluorouridine monophosphate) → Inhibits the enzyme thymidylate synthase, which blocks the synthesis of deoxythymidine triphosphate (dTTP). This severely disrupts DNA synthesis and repair.
- FUTP (fluorouridine triphosphate) → Falsely incorporates into RNA, disrupting RNA processing, function, and subsequent protein synthesis.
By halting both DNA and RNA functions, the drug induces apoptosis in rapidly dividing cancer cells.
Seguridad y advertencias
Contraindicaciones
- CATS (Do NOT use in any form, including topical)
- Patients with known hypersensitivity to the drug
- Patients in poor nutritional states
- Patients with depressed or reduced bone marrow function
- Patients with concurrent serious infections
- Pregnancy (Known teratogen - FDA Category D)
- Cats (strictly contraindicated due to fatal neurotoxicity)
- Patients with severe bone marrow suppression
- Patients with severe hepatic or renal impairment (unless dose is adjusted)
- Pregnancy and lactation
Efectos adversos
- Dose-dependent myelosuppression (leukopenia, thrombocytopenia)
- Gastrointestinal toxicity (nausea, vomiting, hemorrhagic diarrhea, GI ulceration/sloughing, stomatitis)
- Neurotoxicity (ataxia, disorientation, seizures)
- Fatal neurotoxicity in cats (even with topical exposure)
- Anorexia
- Diarrhoea
- Leucopenia (nadir between 7 and 14 days)
- Anaemia
- Alopecia
- Hyperpigmentation
- Dermatitis
- Cerebellar ataxia
Precauciones
Fluorouracil has a very narrow therapeutic index and should only be administered by clinicians experienced with cancer chemotherapeutic agents.
Feline Toxicity: Cats develop severe, potentially fatal neurotoxicity. It is contraindicated in cats in any form.
Reproductive Safety: 5-FU is a known teratogen. Pregnant women and pregnant veterinary staff should avoid handling this medication or the bodily fluids/waste of treated animals. If a nursing dam requires treatment, milk replacer should be used as the drug inhibits DNA/RNA synthesis.
Interacciones farmacológicas
May increase the gastrointestinal toxic effects of 5-FU
Inhibits the metabolism of 5-FU, potentially increasing toxicity
Synergism in human oncology, but combination may be more toxic in small animals
Synergistic if administered before 5-FU; antagonistic if administered afterwards
Increases the cytotoxicity of 5-FU
Monitorización
- CBCs (nadirs usually occur between days 9-14 with recovery by day 30)
- Gastrointestinal adverse effects (vomiting, diarrhea, anorexia)
- Central nervous system adverse effects (ataxia, seizures)
- Liver enzymes (alkaline phosphatase, serum transaminase), serum bilirubin, and lactic dehydrogenase (may increase)
- Tumor response/Efficacy
- Complete Blood Count (CBC) to monitor for leucopenia and thrombocytopenia (nadir 7-14 days)
- Renal function parameters
- Hepatic function parameters
- Gastrointestinal signs (vomiting, diarrhea, stomatitis)
- Neurological signs
Farmacocinética
Vida media
Absorción
Administered systemically via the IV route.
Distribución
Primarily distributed into tumor cells, intestinal mucosa, liver, and bone marrow.
Metabolismo
Converted via intracellular mechanisms to active metabolites (FUMP and FUTP); the majority of the drug is metabolized by the liver.
Eliminación
A small amount (about 15% of dose) is excreted unchanged into the urine.
Sobredosis
Overdoses are extremely serious and potentially fatal.
- Dogs: The lowest reported toxic dose is 8.6 mg/kg (mild GI irritation/vomiting). Seizures and death have been reported at doses as low as 10.3 mg/kg, with survival rates potentially as low as 25%.
- Cats: Very small ingestions (such as licking human topical creams) can cause death.
Clinical Signs: Onset is rapid (30 minutes to 6 hours). Signs include acute nausea, vomiting, hemorrhagic diarrhea, abdominal pain, GI sloughing, ataxia, severe nonresponsive seizures, severe dose-dependent myelosuppression affecting all cell lines, metabolic acidosis, and multi-organ failure.
Treatment:
- Aggressive GI decontamination and protection if ingestion was very recent (though rapid onset may render this ineffective).
- Intensive supportive care: antiemetics, fluid support, pain control, and temperature regulation.
- Seizure control: Diazepam is often unrewarding; barbiturates or general anesthesia are frequently required.
- Broad-spectrum antibiotics to prevent secondary infections.
- Filgrastim (Neupogen®) can be considered to stimulate bone marrow stem cell proliferation in dogs.
- Intensive hematologic monitoring (CBCs every 3-4 days) for at least 3-4 weeks.
Productos disponibles
Formulaciones
- Injection solution
- Topical solution
- Injectable solution: 250 mg/vial, 500 mg/vial, 2500 mg/vial
- Topical cream: 5%
Etiquetado para humanos
- Fluorouracil Injection: 50 mg/mL in 10 mL, 20 mL, 50 mL, & 100 mL vials and 10 mL amps (Adrucil®; generic)
- Topical creams and solutions: 0.5% to 5% (used for actinic keratoses and superficial basal cell carcinomas)
- Efudix 5% cream
- Fluorouracil injectable solutions (various generics)
Estado regulador
Human-approved drug used under the cascade.
POM. Used under the prescribing cascade.
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Store injection between 15-30°C; avoid freezing and exposure to light. Slight color changes in the solution can be ignored. If a precipitate forms, the solution can be heated to 60°C and shaken vigorously to redissolve the drug. Cool to body temperature before administering. If unsuccessful in redissolving the drug, it should not be used.
Información para el cliente
ADVERTENCIA CRÍTICA PARA PROPIETARIOS DE GATOS: Las cremas tópicas de uso humano que contienen 5-FU (utilizadas para lesiones cutáneas) son altamente tóxicas y frecuentemente mortales para los gatos. Incluso un pequeño lamido o caminar sobre un área tratada y luego acicalarse puede causar la muerte. Mantenga todos estos medicamentos estrictamente fuera del alcance.
- Efectos secundarios graves: Entienda que este es un fármaco de quimioterapia potente. Puede causar malestar gastrointestinal grave, supresión de la médula ósea (aumentando el riesgo de infección) y signos neurológicos.
- Monitoreo: Es obligatorio el cumplimiento estricto de las citas de seguimiento para análisis de sangre (CBC) para asegurar que los recuentos de glóbulos blancos de su mascota se mantengan en niveles seguros.
- Seguridad en el hogar: Debido a que este fármaco es un teratógeno conocido (puede causar defectos congénitos) y se excreta en los fluidos corporales, las mujeres embarazadas, las madres lactantes y los niños deben evitar manipular el medicamento o los desechos de la mascota (orina/heces) durante varios días después del tratamiento. Use guantes al limpiar accidentes.
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.