Nitrofurantoína
Nitrofurantoin
Synthetic nitrofuran antibacterial
También conocido como: Macrodantin · Macrobid · Furadantin · furadoninum · nitrofurantoinum · Nitrofurantoine
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 |
|---|---|---|---|---|---|
| Prevention of re-infections with gram-negative organisms | 4 mg/kg | PO | q24h | Long-term | 🌎 NA |
| Recurrent UTI (Conventional dose) | 4 mg/kg | PO | q8h | — | 🌎 NA |
| Recurrent UTI (Prophylactic dose) | 3-4 mg/kg | PO | q24h | — | 🌎 NA |
| Susceptible bacterial urinary tract infections | 4 mg/kg | PO | q6-8h | — | 🌎 NA |
| Susceptible bacterial urinary tract infections | 5 mg/kg | PO | q8h | — | 🌎 NA |
| Susceptible bacterial urinary tract infections | 4.4 mg/kg | PO | q8h | — | 🌎 NA |
| Urinary tract infections (lower UTI only) | 4.4-5 mg/kg | PO | q8h | As directed by culture and sensitivity | 🌍 EU |
- Prevention of re-infections with gram-negative organisms: Give once a day immediately before bedtime after the dog has urinated. Only use after extensive search for underlying cause and after effective treatment of existing UTI.
- Recurrent UTI (Prophylactic dose): Should be given at night after micturition and immediately before bedtime.
- Susceptible bacterial urinary tract infections: Listed as three times daily.
- Urinary tract infections (lower UTI only): For urinary tract infections only. Not for pyelonephritis.
Gatos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| Susceptible bacterial urinary tract infections | 5 mg/kg | PO | q8h | — | 🌎 NA |
| Recurrent UTI (Conventional dose) | 4 mg/kg | PO | q8h | — | 🌎 NA |
| Recurrent UTI (Prophylactic dose) | 3-4 mg/kg | PO | q24h | — | 🌎 NA |
| Susceptible bacterial urinary tract infections | 4 mg/kg | PO | q6-8h | — | 🌎 NA |
| Urinary tract infections (lower UTI only) | 4.4-5 mg/kg | PO | q8h | As directed by culture and sensitivity | 🌍 EU |
- Recurrent UTI (Prophylactic dose): Should be given at night after micturition and immediately before bedtime.
- Urinary tract infections (lower UTI only): For urinary tract infections only. Not for pyelonephritis.
Caballos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| Susceptible urinary tract infections | 2.5-4.5 mg/kg | PO | q8h | — | 🌎 NA |
| Susceptible urinary tract infections | 10 mg/kg | PO | q24h | — | 🌎 NA |
- Susceptible urinary tract infections: Listed as three times daily.
- Susceptible urinary tract infections: Listed as daily.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
Nitrofurantoína es un agente antibacteriano nitrofuranos sintético utilizado principalmente como antiséptico del tracto urinario.
- Eficacia específica por sitio: Debido a que se elimina rápidamente en la orina, alcanza concentraciones elevadas en el tracto urinario inferior, pero no alcanza concentraciones terapéuticas en la circulación sistémica o en los tejidos. Por lo tanto, es altamente eficaz para infecciones del tracto urinario inferior (ITU), pero es ineficaz para infecciones sistémicas, pielonefritis (infecciones renales) o abscesos perirrenales.
- Espectro de actividad: Es activo contra muchos organismos gramnegativos y grampositivos, incluyendo E. coli, Klebsiella, Staphylococcus y Enterococcus. Es notablemente ineficaz contra Pseudomonas spp. y la mayoría de las cepas de Proteus.
- Perla clínica: Debido a la creciente resistencia a los antibióticos de primera línea, la nitrofurantoína a menudo se reserva para ITUs inferiores multirresistentes, particularmente aquellas causadas por cepas resistentes de E. coli o especies de Enterococcus.
Mecanismo de acción
Nitrofurantoin can be bacteriostatic or bactericidal depending on the concentration and organism susceptibility.
- Mechanism: Inside the bacterial cell, nitrofurantoin is reduced by bacterial flavoproteins to highly reactive intermediate compounds.
- Pathway: Reactive intermediates → attack bacterial ribosomal proteins and other macromolecules → inhibit protein synthesis, aerobic energy metabolism (specifically acetyl coenzyme A), DNA synthesis, RNA synthesis, and cell wall synthesis.
- Environmental Factor: It exhibits significantly greater antibacterial activity in acidic environments.
Seguridad y advertencias
Contraindicaciones
- Renal impairment (decreased efficacy and increased risk of systemic toxicity)
- Known hypersensitivity to nitrofurantoin
- Pregnant patients at term (risk of hemolytic anemia in neonates)
- Rats (high risk of neurotoxicity)
- Significant renal impairment (decreased excretion leads to toxic serum levels)
- Pregnancy (mutagenic properties)
- Pyelonephritis
- Systemic infections outside the urinary tract
- Food-producing animals
Efectos adversos
- Gastrointestinal disturbances (vomiting, nausea, diarrhea)
- Hepatopathy (can be severe or chronic)
- Myasthenic-like effects (rare, reversible in dogs)
- Infertility in male dogs
- Peripheral neuropathy (rare)
- Hemolytic anemia (rare)
- Pneumonitis (rare)
- Emesis
- Diarrhoea
- Gastrointestinal bleeding
- Hepatotoxicity
- Peripheral neuritis (rare)
- Pulmonary complications (rare)
- Thrombocytopenia (at high doses)
- Anaemia (at high doses)
- Leucopenia (at high doses)
- Prolonged bleeding times (at high doses)
Precauciones
Renal Function Warning: Do not use in patients with compromised renal function. The drug relies on renal excretion to reach the site of infection (the bladder); poor kidney function means the drug won't work for the UTI and will accumulate in the blood, causing toxicity.
- Hepatotoxicity: Can cause drug-induced hepatopathy. Monitor liver enzymes if adverse effects are suspected, especially during long-term prophylactic use.
- Reproductive Warning: May cause infertility in male dogs. Use with caution in breeding animals.
- Lab Interference: May cause false-positive urine glucose results if using cupric-sulfate solutions (e.g., Clinitest). May also cause decreases in blood glucose and increases in serum creatinine, bilirubin, and ALP.
Interacciones farmacológicas
Nitrofurantoin may antagonize the antimicrobial activity of fluoroquinolones; concomitant use should be avoided.
May increase the oral bioavailability and absorption of nitrofurantoin.
May inhibit the oral absorption of nitrofurantoin.
May inhibit the renal excretion of nitrofurantoin, potentially increasing systemic toxicity and reducing its effectiveness in the urinary tract.
Delays gastric emptying time and increases absorption/bioavailability of nitrofurantoin
Delays gastric emptying time and increases absorption/bioavailability of nitrofurantoin
Antagonism of antibacterial efficacy
May increase the hyperkalaemic effects of spironolactone
Significantly decreases the antibacterial activity of nitrofurantoin
Monitorización
- Clinical efficacy (resolution of UTI symptoms, negative urine cultures)
- Adverse effects (especially GI upset)
- Periodic liver function tests (especially with chronic/prophylactic therapy)
- Resolution of clinical signs of UTI
- Urine culture and sensitivity
- Renal function (BUN, Creatinine)
- Complete Blood Count (CBC) if used long-term or at high doses
- Liver enzymes
Farmacocinética
Vida media
Absorción
Rapidly absorbed from the GI tract. Presence of food enhances absorption. Macrocrystalline forms are absorbed more slowly, resulting in less GI upset and prolonged urine levels.
Distribución
Therapeutic levels in systemic circulation are not maintained due to rapid elimination. Approximately 20-60% is bound to serum proteins. Crosses the placenta; minimal quantities found in milk.
Metabolismo
Some of the drug is metabolized, primarily in the liver.
Eliminación
Rapidly eliminated. Approximately 40-50% is excreted into urine unchanged via both glomerular filtration and tubular secretion. Peak urine levels occur within 30 minutes of dosing.
Sobredosis
Because the drug is rapidly absorbed and excreted, patients with normal renal function usually require little therapy for mild overdoses.
- Massive Overdose: If ingestion was recent, empty the gut using standard protocols (emesis/gastric lavage).
- Monitoring: Monitor closely for gastrointestinal distress, hepatotoxicity, and neurologic signs. Provide supportive care as needed.
Productos disponibles
Formulaciones
- Oral capsules (macrocrystals)
- Oral capsules (monohydrate/macrocrystals)
- 50 mg tablet
- 100 mg tablet
- 25 mg/5 ml oral suspension
Etiquetado para humanos
- Nitrofurantoin Macrocrystals Oral Capsules: 25 mg, 50 mg & 100 mg (Macrodantin, generic)
- Nitrofurantoin Monohydrate/Macrocrystals Oral Capsules: 100 mg (Macrobid, generic)
- Nitrofurantoin Oral Suspension: 25 mg/5 mL (5 mg/mL) (Furadantin)
- Nitrofurantoin 50 mg tablets
- Nitrofurantoin 100 mg tablets
- Nitrofurantoin 25 mg/5 ml oral suspension
Estado regulador
Banned for use in food-producing animals (Annex IV / Table 2 substance).
Human POM used under the prescribing cascade. Banned in food-producing animals.
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Store in tight containers at room temperature and protect from light. Do not freeze the oral suspension. Nitrofurantoin will decompose if it comes into contact with metals other than aluminum or stainless steel.
Información para el cliente
La nitrofurantoína es un antibiótico utilizado específicamente para tratar infecciones de la vejiga. Se concentra en la orina para eliminar las bacterias, pero no funciona para infecciones en otras partes del cuerpo.
- Administrar con comida: Siempre administre este medicamento con una comida o un premio. Esto reduce significativamente el malestar estomacal (vómitos) y ayuda a que el cuerpo absorba mejor el fármaco.
- El horario es clave: Si su mascota recibe una dosis preventiva una vez al día, adminístrela justo antes de dormir, inmediatamente después de su última salida para orinar de la noche. Esto permite que el medicamento permanezca en la vejiga durante la noche para combatir las bacterias.
- Vigile los efectos secundarios: El efecto secundario más común es el vómito. Si el vómito es severo o persiste, contacte a su veterinario.
- Advertencia hepática: En casos raros, este medicamento puede afectar el hígado. Contacte a su veterinario de inmediato si nota coloración amarillenta en los ojos o encías, letargo severo o pérdida de apetito.
- Termine la receta: Incluso si su mascota parece sentirse mejor, termine todo el ciclo de antibióticos para evitar que la infección regrese o se vuelva resistente.
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.