Fenilbutazona
Phenylbutazone
Phenylbutazone (synthetic pyrazolone derivative)
También conocido como: Butazolidin · Phenylbute · butadiene · fenilbutazona · phenylbutazonum
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
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 |
|---|---|---|---|---|---|
| General inflammation/pain | 14 mg/kg | PO | three times daily initially | — | 🌎 NA |
| General inflammation/pain | 15-22 mg/kg | PO | q12h | — | 🌎 NA |
| Analgesia | 1-5 mg/kg | PO | q8h | — | 🌎 NA |
- General inflammation/pain: Maximum of 800 mg/day regardless of weight; titrate dose to lowest effective dose. Rarely used today.
Caballos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| To reduce pain or pyrexia associated with pleuropneumonia | 2.2-4.4 mg/kg | PO or IV | q12h | first week of treatment or longer | 🌎 NA |
| General musculoskeletal inflammation | 1-2 grams per 454 kg (1000 lb.) horse IV, or 2-4 grams per 454 kg (1000 lb.) horse PO | IV or PO | daily | Limit IV administration to no more than 5 successive days | 🌎 NA |
| Adjunctive treatment of colic (to reduce endotoxic effects) | 2.2 mg/kg | PO or IV | twice daily | — | 🌎 NA |
| Adjunctive treatment of laminitis | Initial dose of 4 grams, immediately decreased to 1 to 1.5 grams | PO or IV | twice daily | — | 🌎 NA |
| Osteoarthritis | 2.2 mg/kg | PO | twice daily | — | 🌎 NA |
- General musculoskeletal inflammation: Do not exceed 4 grams/day. Use high end of dosage range initially, then titrate to lowest effective dose. Injection must be made slowly and with care.
- Adjunctive treatment of laminitis: Dose for an average adult-sized horse. Lower dose is used to keep the horse comfortable, but not relieve pain to the extent the horse moves around excessively.
- Osteoarthritis: Minimal dose to control pain.
Ganado
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| General inflammation/pain | 4-8 mg/kg PO or 2-5 mg/kg IV | PO or IV | — | — | 🌎 NA |
| General inflammation/pain | 10-20 mg/kg PO, then 2.5-5 mg/kg q24h or 10 mg/kg every 48 hours PO | PO | q24h or q48h | — | 🌎 NA |
- General inflammation/pain: Extralabel use prohibited in female dairy cattle 20 months of age or older.
- General inflammation/pain: Extralabel use prohibited in female dairy cattle 20 months of age or older.
Cerdos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| General inflammation/pain | 4 mg/kg | IV or PO | q24h | — | 🌎 NA |
| General inflammation/pain | 4-8 mg/kg PO or 2-5 mg/kg IV | PO or IV | — | — | 🌎 NA |
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
La fenilbutazona (conocida comúnmente como "bute") es un antiinflamatorio no esteroideo (AINE) clásico, no selectivo, perteneciente a la clase de las pirazolonas.
Nota clínica: Aunque históricamente se utilizó en muchas especies por sus potentes propiedades analgésicas, antiinflamatorias y antipiréticas, su uso en la medicina veterinaria moderna está restringido casi exclusivamente a la práctica equina para el manejo del dolor musculoesquelético (p. ej., laminitis, osteoartritis).
En animales pequeños (perros y gatos), ha sido reemplazada en gran medida por AINE selectivos de la COX-2 más seguros (como carprofen o meloxicam) debido al alto riesgo de efectos adversos graves, incluyendo discrasias sanguíneas, hepatotoxicidad y ulceración gastrointestinal severa. Está estrictamente regulada en animales destinados al consumo humano debido a preocupaciones de seguridad sobre la toxicidad en la médula ósea (anemia aplásica).
Mecanismo de acción
Phenylbutazone acts primarily by inhibiting the cyclooxygenase (COX) enzymes (both COX-1 and COX-2), which prevents the conversion of arachidonic acid → prostaglandins and thromboxanes.
- ↓ Prostaglandins → Reduced inflammation, analgesia, and antipyresis.
- ↓ Thromboxane A2 → Decreased platelet aggregation.
Pharmacological Note: Phenylbutazone is metabolized in the liver to oxyphenbutazone, an active metabolite that contributes significantly to its prolonged efficacy (often >24 hours) despite a relatively short plasma half-life. The irreversible binding of phenylbutazone to cyclooxygenase also extends its duration of action. It also possesses mild uricosuric properties.
Seguridad y advertencias
Contraindicaciones
- Known hypersensitivity to phenylbutazone or other NSAIDs
- History of or preexisting hematologic or bone marrow abnormalities
- Preexisting gastrointestinal ulcers
- Food-producing animals (especially female dairy cattle 20 months of age or older)
- Lactating dairy cattle
- Pre-existing gastrointestinal ulceration
- Renal impairment
- Hepatic impairment
- Hematological disorders
- Use in food-producing animals (banned in many jurisdictions)
Efectos adversos
- Gastrointestinal and oral erosions/ulcers
- Hypoalbuminemia (especially in foals/ponies)
- Renal papillary necrosis and azotemia
- Sodium and water retention (edema)
- Blood dyscrasias (agranulocytosis, aplastic anemia)
- Hepatotoxicity
- Severe tissue necrosis and sloughing (if injected IM or SC)
- CNS stimulation and seizures (if injected intracarotid)
- Gastrointestinal ulceration and bleeding
- Bone marrow suppression (aplastic anemia, leukopenia)
Precauciones
Use with extreme caution in foals and ponies due to increased incidence of hypoproteinemia and GI ulceration. Avoid in horses with known or suspected Equine Gastric Ulcer Syndrome (EGUS). Use cautiously in animals with preexisting renal disease or congestive heart failure (CHF) due to potential for sodium/water retention and decreased renal blood flow. May mask clinical signs of lameness in horses. WARNING: Do not administer injectable preparations IM or SC as it is highly irritating and causes necrosis/sloughing. Intracarotid injections may cause CNS stimulation and seizures.
Interacciones farmacológicas
Phenylbutazone may antagonize the increased renal blood flow effects caused by furosemide.
Concurrent administration may increase the chances of hepatotoxicity developing.
Concurrent use increases the potential for adverse GI and renal reactions. (Note: 'Stacking' with ketoprofen shows synergistic toxicity).
May increase the risk of hematologic and/or renal adverse reactions.
Phenylbutazone may increase the plasma half-life of penicillin G.
Phenylbutazone could potentially displace sulfonamides from plasma proteins, increasing the risk for adverse effects.
Phenylbutazone could potentially displace warfarin from plasma proteins, increasing the risk for bleeding.
Increased risk of gastrointestinal ulceration
Increased risk of gastrointestinal ulceration and renal toxicity
Displacement from plasma proteins leading to increased free drug concentrations
Monitorización
- Analgesic, anti-inflammatory, and antipyretic efficacy
- Complete blood counts (CBC) with chronic therapy (weekly early in therapy, biweekly later)
- Urinalysis and renal function parameters (serum creatinine/BUN) with chronic therapy
- Plasma protein determinations (especially in ponies, foals, and debilitated animals)
- Complete Blood Count (CBC)
- Renal function (BUN, Creatinine)
- Liver enzymes
- Clinical signs of GI bleeding (melena)
Farmacocinética
Vida media
Absorción
Absorbed from both the stomach and small intestine following oral administration.
Distribución
Distributed throughout the body with highest levels attained in the liver, heart, lungs, kidneys, and blood. Plasma protein binding in horses exceeds 99%. Crosses the placenta and is excreted into milk.
Metabolismo
Nearly completely metabolized in the liver, primarily to oxyphenbutazone (active) and gamma-hydroxyphenylbutazone.
Eliminación
Excreted primarily in the urine. More rapidly excreted into alkaline than acidic urine. Oxyphenbutazone can be detected in horse urine up to 48 hours after a single dose.
Sobredosis
Manifestations of acute overdosage include prompt respiratory or metabolic acidosis with compensatory hyperventilation, seizures, coma, and acute hypotensive crisis.
- Systemic Effects: Clinical signs of renal failure (oliguric, proteinuria, hematuria), liver injury (hepatomegaly, jaundice), bone marrow depression, and severe GI ulceration/perforation may develop.
- Dogs: Common signs include ataxia, seizures, tachycardia, trembling, tremors, vomiting, and tachypnea. Oral LD50 is 332 mg/kg.
- Horses: Common signs include colic, anorexia, and ataxia.
Treatment: Standard overdose procedures should be followed (e.g., empty gut following oral ingestion). Institute supportive treatment as necessary. Intravenous diazepam can be used to help control seizures. Monitor fluid therapy carefully, as phenylbutazone may cause fluid retention.
Productos disponibles
Formulaciones
- Tablets
- Oral powder
- Oral paste
- Injection
- 100 mg tablet
- 200 mg tablet
Veterinario
- Phenylbutazone Tablets: 100 mg, 200 mg, 1 gram
- Phenylbutazone Oral Powder: 1 gram in 10 grams of powder
- Phenylbutazone Paste Oral Syringes: 6 grams or 12 grams/syringe
- Phenylbutazone Injection: 200 mg/mL in 100 mL vials
- 100 mg tablets (Currently unavailable)
- 200 mg tablets (Currently unavailable)
Estado regulador
POM. Licensed forms for small animals are currently unavailable. Prohibited in food-producing animals.
POM-V. Licensed forms for small animals are currently unavailable. Prohibited in food-producing animals.
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Oral products should be stored in tight, child-resistant containers if possible. The injectable product should be stored in a cool place (46-56° F) or kept refrigerated.
Información para el cliente
Para propietarios de caballos:
- La "bute" es altamente efectiva para el manejo del dolor óseo y articular. Administre siempre la dosis exacta prescrita por su veterinario.
-
ADVERTENCIA CRÍTICA: Nunca administre la forma líquida inyectable en el músculo (IM) o bajo la piel (SC). Debe ser administrada estrictamente por vía intravenosa (IV) por un profesional. Una inyección incorrecta causa daño tisular severo y necrosis.
- Observe de cerca signos de úlceras estomacales o problemas renales: pérdida de apetito, diarrea, signos de cólico o hinchazón en las patas o el vientre. Suspenda la medicación y contacte a su veterinario si ocurren estos síntomas.
Para propietarios de perros:
- Este medicamento rara vez se utiliza en perros hoy en día debido a la disponibilidad de alternativas más seguras. Si se prescribe, monitoree a su perro muy de cerca para detectar vómitos, heces oscuras/alquitranadas o letargo, y contacte a su veterinario inmediatamente si ocurren.
Restricciones en animales de consumo:
- Estrictamente prohibido por la FDA para su uso en vacas lecheras hembras de 20 meses de edad o mayores.
- Si se utiliza fuera de etiqueta en ganado de carne, se aplican estrictos tiempos de retiro (p. ej., 1 dosis = 30 días, 2 dosis = 35 días). Consulte a su veterinario.
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.