Sulfadiazina/Trimetoprima y Sulfametoxazol/Trimetoprima
Sulfadiazine/Trimethoprim and Sulfamethoxazole/Trimethoprim
Trimethoprim/Sulfadiazine, Trimethoprim/Sulfamethoxazole
También conocido como: Co-trimoxazole · Tribrissen · Bactrim · Septra · Tucoprim · Uniprim · Di-Biotic · Cotrim · Sulfatrim · Trivetrin · Borgal · SMX-TMP · trimethoprim-sulfamethoxazole · sulfadiazine-trimethoprim · TMP-SDZ · Co-trimazine
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
Evidencia posológica v13 auditada
Evidencia estructurada para el cálculoCoccidiosis
- q12-24h
NA
Contexto clínico obligatorio (3)
- NOTE: There is significant controversy regarding the frequency of administration of these drugs. See Pharmacokinetics for more information. Unless otherwise noted, doses are for combined sulfa-/trimethoprim. See Monitoring if treatment is expected to be longer than 7 days.
- Bacterial cystitis (extra-label): Potentiated sulfonamides (ie, sulfa-/ trimethoprim, sulfadimethoxine/ormetoprim) are first-tier drugs only if regional pathogen susceptibility patterns are known. 32
- Unless otherwise instructed by the manufacturer, sulfa-/trimethoprim products should be stored at room temperature of 20°C to 25°C (68°F-77°F) in tight containers and protected from freezing. Shake suspensions well before use.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
Las sulfonamidas potenciadas (a menudo denominadas TMS, SMZ-TMP o co-trimoxazol) son combinaciones antimicrobianas bactericidas de amplio espectro utilizadas extensamente en medicina veterinaria.
Perlas clínicas clave:
- Excelente penetración tisular: Altamente liposolubles, lo que permite alcanzar concentraciones terapéuticas en tejidos de difícil acceso, incluyendo la próstata, la barrera hematoencefálica (SNC) y el ojo.
- Amplio espectro: Efectivas contra muchos organismos Gram-positivos y Gram-negativos, incluyendo muchas cepas de Staphylococcus resistente a la meticilina (MRSA/MRSP), Nocardia y ciertos protozoos (Toxoplasma, Coccidia, Pneumocystis).
- Inactivación por pus: La eficacia del fármaco se ve significativamente inhibida por restos purulentos y tejido necrótico (ricos en PABA y timidina). Los abscesos deben ser drenados para que el fármaco sea efectivo.
- Sensibilidad racial: Los Doberman Pinschers tienen una susceptibilidad conocida, específica de la raza, a la enfermedad por inmunocomplejos multisistémicos inducida por sulfonamidas (hipersensibilidad).
- Formulaciones: Aunque existen productos de trimetoprima/sulfadiazina aprobados para uso veterinario, muchos profesionales utilizan trimetoprima/sulfametoxazol (Bactrim®, Septra®) aprobado para humanos de forma off-label con eficacia similar.
Mecanismo de acción
Potentiated sulfas exhibit synergistic, bactericidal activity by sequentially blocking the bacterial folic acid synthesis pathway. Mammalian cells are largely unaffected because they utilize preformed dietary folate rather than synthesizing it.
- Sulfonamides (Bacteriostatic alone): Act as structural analogues of para-aminobenzoic acid (PABA). They competitively inhibit the bacterial enzyme dihydropteroate synthase → blocks the conversion of PABA to dihydrofolic acid (DFA).
- Trimethoprim (Bactericidal alone): Reversibly inhibits the bacterial enzyme dihydrofolate reductase → blocks the conversion of DFA to tetrahydrofolic acid (THFA).
- Synergy: The sequential blockade completely depletes THFA, an essential cofactor for bacterial DNA and RNA synthesis, leading to rapid bacterial cell death.
Pharmacologic Note: The optimal in vitro ratio for most susceptible bacteria is 1:20 (trimethoprim:sulfa), but synergistic activity occurs across a wide range (1:1 to 1:40). The serum concentration of the trimethoprim component is generally considered the primary driver of efficacy.
Seguridad y advertencias
Contraindicaciones
- Hypersensitivity to sulfonamides, thiazides, or sulfonylurea agents
- Severe renal or hepatic impairment
- Doberman pinschers (highly susceptible to immune complex disease)
- Marked blood dyscrasias
- Animals intended for food (in the USA/certain jurisdictions)
Efectos adversos
- Dogs: Keratoconjunctivitis sicca (KCS/dry eye - potentially irreversible)
- Dogs: Hypersensitivity reactions (Type 1 anaphylaxis or Type 3 serum sickness, polyarthritis, urticaria, facial swelling)
- Dogs: Acute neutrophilic hepatitis with icterus, idiosyncratic hepatic necrosis
- Dogs: Vomiting, anorexia, diarrhea
- Dogs: Hemolytic anemia, agranulocytosis
- Dogs: Hypothyroidism (with extended therapy)
- Dogs: Crystalluria, hematuria, polyuria, polydipsia
- Cats: Anorexia, crystalluria, hematuria, leukopenias, anemias
- Horses: Transient pruritus (after IV injection), diarrhea, hypersensitivity, hematologic effects
- Injection site reactions: Swelling, pain, tissue damage (IM, SC, or extravasation)
Precauciones
Use with caution in patients with pre-existing hepatic or renal disease. Because of its potential for crystallization in the urine, avoid use in dogs known to have uroliths, at increased risk for developing uroliths, or those with highly concentrated (dehydrated) or acidic urine. Potentially teratogenic (cleft palate reported); weigh risk vs. benefit in pregnant animals. Use with caution in nursing animals as sulfonamides are excreted in milk and may cause kernicterus in neonates.
Interacciones farmacológicas
May cause toxic delirium (reported in humans)
May decrease the bioavailability of sulfonamides if administered concurrently
May increase the risk of nephrotoxicity
May increase digoxin levels
May increase risk for thrombocytopenia
May potentiate hypoglycemic effects
May displace from plasma proteins and increase risk for toxic effects; can also interfere with MTX assays
May increase half-life of phenytoin
May decrease efficacy of the antidepressant
May prolong INR/PT and increase bleeding risk
Monitorización
- Clinical efficacy
- Adverse effects (GI, hypersensitivity)
- Complete blood counts (CBC) periodically with chronic therapy
- Schirmer Tear Test (STT) in dogs to monitor tear production (e.g., at 5 days, then every 2-3 weeks)
- Thyroid function tests (baseline and ongoing) for dogs on long-term treatment
Farmacocinética
Vida media
Absorción
Well absorbed after oral administration, with peak levels occurring about 1-4 hours after dosing. More slowly absorbed after subcutaneous administration. In ruminants >8 weeks old, trimethoprim is trapped in the ruminoreticulum after oral administration and undergoes degradation.
Distribución
Well distributed in the body. Enters CSF at about 50% of serum levels when meninges are inflamed. Crosses the placenta and distributes into milk. Relatively well distributed into the prostate. Volume of distribution for trimethoprim: 1.49 L/kg (dogs), 0.59-1.51 L/kg (horses). Vd for sulfadiazine in dogs is 1.02 L/kg.
Metabolismo
Metabolized by the liver. Sulfas are primarily acetylated and conjugated with glucuronic acid. Trimethoprim is metabolized to oxide and hydroxylated metabolites. Trimethoprim may be more extensively metabolized in the liver in adult ruminants.
Eliminación
Renally excreted unchanged via glomerular filtration and tubular secretion, as well as hepatic metabolism. Trimethoprim is rapidly eliminated from serum but may persist longer in tissues.
Sobredosis
Manifestations of acute overdosage include GI distress (nausea, vomiting, diarrhea), CNS toxicity (depression, headache, confusion), facial swelling, bone marrow depression, and elevated serum aminotransferases.
Treatment:
- Oral Overdose: Empty the stomach following usual protocols and initiate symptomatic/supportive therapy.
- Fluid Therapy: Maintain hydration. Acidification of urine may increase renal elimination of trimethoprim but increases the risk of sulfonamide crystalluria (especially with sulfadiazine).
- Monitoring: Monitor complete blood counts and liver parameters.
- Bone Marrow Suppression: If severe and associated with chronic overdose, may be treated with folinic acid (leucovorin).
- Note: Peritoneal dialysis is not effective in removing TMP or sulfas from circulation.
Productos disponibles
Formulaciones
- Oral Paste
- Sterile Injection
- Oral Powder
- Oral Tablets
- Oral Suspension
Veterinario
- Trimethoprim/Sulfadiazine Oral Paste: 67 mg TMP / 333 mg SDZ per gram (Tribrissen 400 Oral Paste)
- Trimethoprim/Sulfadiazine Sterile Injection: 48% (Di-Biotic 48%, Tribrissen 48% Injection)
- Trimethoprim/Sulfadiazine Powder: 67 mg TMP / 333 mg SDZ per gram (Tucoprim, Uniprim)
- Trimethoprim/Sulfadoxine (Canada): Trivetrin, Borgal
Etiquetado para humanos
- Trimethoprim Tablets: 100 mg, 200 mg (Proloprim, Trimpex)
- Trimethoprim/Sulfamethoxazole (TMP-SMZ) Tablets: 80 mg TMP / 400 mg SMX (Bactrim, Septra)
- Trimethoprim/Sulfamethoxazole Double Strength (DS) Tablets: 160 mg TMP / 800 mg SMX (Bactrim DS, Septra DS)
- Trimethoprim/Sulfamethoxazole Oral Suspension: 8 mg TMP / 40 mg SMX per mL (Septra, Cotrim Pediatric, Sulfatrim)
- Trimethoprim/Sulfamethoxazole Injection: 16 mg TMP / 80 mg SMX per mL
Estado regulador
Sin datos reguladores para: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Unless otherwise instructed by the manufacturer, trimethoprim/sulfadiazine and co-trimoxazole products should be stored at room temperature (15-30°C) in tight containers.
Información para el cliente
Guía importante para los propietarios de mascotas:
- La hidratación es crucial: Asegúrese de que su mascota tenga acceso libre a abundante agua fresca en todo momento mientras reciba este medicamento. La deshidratación puede provocar la formación de cristales del fármaco en los riñones o la orina.
- Observe los ojos (perros): Este medicamento puede disminuir la producción de lágrimas, lo que lleva a una condición llamada "ojo seco" (queratoconjuntivitis seca). Contacte a su veterinario inmediatamente si nota que su perro entrecierra los ojos, se los frota, presenta enrojecimiento o secreción ocular espesa de color amarillo/verde.
- Reacciones alérgicas: Los Doberman Pinschers y algunos perros de razas grandes son más propensos a reacciones alérgicas. Suspenda el medicamento y llame a su veterinario si nota hinchazón facial, urticaria, fiebre inexplicable, rigidez articular/cojera o coloración amarillenta en los ojos o encías.
- Administración: Puede administrarse con o sin comida. Si utiliza la suspensión oral líquida, agítela vigorosamente antes de extraer cada dosis. El líquido no necesita refrigeración.
- Complete el tratamiento: Siempre complete la prescripción completa según las indicaciones de su veterinario, incluso si su mascota parece estar completamente recuperada, para prevenir la resistencia a los antibióticos.
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.