Ampicilina
Ampicillin
Ampicillin sodium, Ampicillin trihydrate
También conocido como: Polyflex · Principen · Amfipen · Ampicare · aminobenzylpenicillin · ampicillinum anhydricum · anhydrous ampicillin · AY-6108 · BRL-1341 · NSC-528986 · P-50 · Ampicillin sodium · Aminopenicillin
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
Evidencia posológica v13 auditada
Evidencia estructurada para el cálculoSusceptible infections (extra-label)
Requiere verificación veterinaria
- q12h
NA
Contexto clínico obligatorio (3)
- ■ Because penicillins usually have minimal toxicity associated with their use, monitoring for efficacy is usually all that is required unless toxic signs develop. Serum levels and therapeutic drug monitoring are not routinely done with these agents.
- Ampicillin trihydrate (Polyflex®) powder for injection should be stored at or below 25°C (77°F), with excursions permitted up to 30°C (86°F). After reconstitution, it is stable for 3 months when refrigerated.
- Ampicillin sodium powder for injection should be stored at room temperature (15°C-30°C [59°F-86°F]). The drug is relatively unstable after reconstitution and should be used within 1 hour of reconstitution. As the concentration of the drug in solution increases, the stability of the drug decreases. Dextrose may also speed the destruction of the drug by acting as a catalyst in the hydrolysis of ampicillin.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
La ampicilina es un antibiótico aminopenicilínico bactericida de amplio espectro y dependiente del tiempo.
Las características farmacológicas clave incluyen:
- Espectro de actividad: Efectivo contra muchos organismos grampositivos (incluidos enterococos sensibles a la penicilina como E. faecium), anaerobios (p. ej., Clostridium spp.) y algunos aerobios gramnegativos (E. coli, Klebsiella, Haemophilus, Proteus mirabilis).
- Resistencia: Al igual que las penicilinas naturales, es altamente susceptible a la inactivación por bacterias productoras de beta-lactamasa (p. ej., Staphylococcus aureus). Es ineficaz contra Pseudomonas aeruginosa, Serratia, Enterobacter y organismos atípicos (Mycoplasma, Rickettsia, hongos).
- Utilidad clínica: Aunque la ampicilina oral ha sido reemplazada en gran medida por la amoxicilina en animales pequeños debido a su superior biodisponibilidad, la ampicilina parenteral sigue siendo una terapia fundamental.
- Formas de sal:
- Ampicilina sódica: Altamente soluble en agua, adecuada para administración IV, proporcionando concentraciones séricas máximas rápidas y elevadas.
- Ampicilina trihidrato: Una forma de depósito para uso IM o SC, que proporciona una absorción más lenta y niveles séricos máximos más bajos (aproximadamente la mitad que la sal sódica). No debe utilizarse cuando se requieren concentraciones inhibitorias mínimas (CIM) elevadas para infecciones sistémicas.
Mecanismo de acción
Ampicillin is a beta-lactam antibiotic that exerts its bactericidal effect by interfering with bacterial cell wall synthesis.
- Mechanism: Ampicillin covalently binds to specific Penicillin-Binding Proteins (PBPs) (primarily transpeptidases) located inside the bacterial cell wall.
- Pathway: Binding to PBPs → inhibition of the final transpeptidation step of peptidoglycan cross-linking → weakening of the cell wall structure → activation of endogenous autolytic enzymes (autolysins) → osmotic lysis and bacterial cell death.
- Pharmacodynamics: Efficacy is time-dependent, meaning the free drug concentration must remain above the Minimum Inhibitory Concentration (MIC) for a significant portion of the dosing interval (typically >40-50% of the interval).
Seguridad y advertencias
Contraindicaciones
- Patients with a known hypersensitivity to penicillins
- Oral administration in patients with septicemia, shock, or grave illness (due to delayed/diminished GI absorption)
- Oral or parenteral use in small hindgut fermenters (rabbits, guinea pigs, chinchillas, hamsters) due to risk of fatal clostridial enterotoxemia
Efectos adversos
- Gastrointestinal upset (anorexia, vomiting, diarrhea)
- Antibiotic-associated diarrhea and superinfections (alteration of gut flora)
- Hypersensitivity reactions (rashes, fever, eosinophilia, anaphylaxis)
- Neurotoxicity (ataxia, seizures) at very high doses or prolonged use
- Elevated liver enzymes (rare)
- Tachypnea, dyspnea, edema, and tachycardia (reported in dogs)
Precauciones
Cross-Reactivity: Use cautiously in patients with documented hypersensitivity to other beta-lactam antibiotics (e.g., cephalosporins, carbapenems), as cross-reactivity can occur.
Species Warning: Severe, potentially fatal enteritis and clostridial enterotoxemia can occur if administered to rabbits, guinea pigs, chinchillas, or hamsters.
Laboratory Interference: May cause false-positive urine glucose determinations when using cupric sulfate solutions (e.g., Clinitest). Glucose oxidase tests are unaffected.
Interacciones farmacológicas
Potential in vitro antagonism; clinical significance is debated but concurrent use is traditionally discouraged.
Ampicillin may decrease the renal excretion of methotrexate, leading to increased levels and potential toxicity.
Competitively blocks the tubular secretion of penicillins, increasing serum levels and prolonging half-life.
In vitro inactivation of aminoglycosides if mixed in the same syringe or fluid bag. May also occur in vivo in patients with severe renal failure.
Antagonism of bactericidal effect due to bacteriostatic action
Antagonism of bactericidal effect due to bacteriostatic action
Antagonism of bactericidal effect due to bacteriostatic action
In vitro inactivation if mixed in the same syringe; however, exhibits synergistic antimicrobial effects when used concurrently in vivo
Monitorización
- Clinical efficacy (resolution of infection signs)
- Adverse effects (GI signs, hypersensitivity reactions)
- Therapeutic drug monitoring is not routinely required due to the wide therapeutic index
Farmacocinética
Vida media
Absorción
Relatively stable in gastric acid. Oral absorption is 30-55% in monogastric animals on an empty stomach; food decreases the rate and extent of absorption. Parenteral trihydrate salt achieves serum levels approximately 1/2 those of a comparable dose of the sodium salt.
Distribución
Widely distributed to many tissues (liver, lungs, muscle, bile, ascitic/pleural/synovial fluids). Volume of distribution is ~0.3 L/kg in dogs, 0.167 L/kg in cats, and 0.16-0.5 L/kg in cattle. Crosses inflamed meninges (10-60% of serum levels). Low levels in aqueous humor, tears, sweat, saliva, and milk. Crosses the placenta. Approximately 20% bound to plasma proteins.
Metabolismo
Some of the drug is metabolized by hydrolysis to inactive penicilloic acids.
Eliminación
Eliminated primarily through renal mechanisms, principally by tubular secretion. Excreted in the urine.
Sobredosis
Acute oral penicillin overdoses are unlikely to cause significant problems other than gastrointestinal distress (vomiting, diarrhea, anorexia).
In humans, very high dosages of parenteral penicillins, particularly in patients with underlying renal disease, have induced CNS effects (e.g., seizures, ataxia). Treatment is generally supportive and symptomatic.
Productos disponibles
Formulaciones
- Powder for injection (Ampicillin sodium)
- Powder for injection suspension (Ampicillin trihydrate)
- Oral capsules
- Powder for oral suspension
Veterinario
- Ampicillin Trihydrate Injection Powder for Suspension: 10 g and 25 g vials (Polyflex)
Etiquetado para humanos
- Ampicillin Sodium Powder for Injection: 250 mg, 500 mg, 1 g, 2 g vials
- Ampicillin Oral Capsules (as trihydrate): 250 mg, 500 mg (Principen)
- Ampicillin Powder for Oral Suspension (as trihydrate): 125 mg/5 mL, 250 mg/5 mL (Principen)
Estado regulador
POM-V classification
POM-V (Prescription Only Medicine - Veterinarian)
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Capsules and powder for oral suspension: Store at room temperature (15-30°C). Reconstituted oral suspension: Stable for 14 days refrigerated (2-8°C) or 7 days at room temperature. Ampicillin trihydrate for injection (Polyflex): Stable for 3 months refrigerated. Ampicillin sodium for injection: Relatively unstable after reconstitution; generally use within 1 hour. Stability decreases as concentration increases. Dextrose speeds destruction. At ≤30 mg/mL in sterile water or 0.9% NaCl, stable up to 48 hours at 4°C.
Información para el cliente
- Administración: A menos que su veterinario indique lo contrario, administre este medicamento por vía oral con el estómago vacío (al menos 1 hora antes de comer o 2 horas después) para asegurar una absorción adecuada.
- Almacenamiento: Mantenga la suspensión oral en el refrigerador y deseche cualquier porción no utilizada después de 14 días. Si se mantiene a temperatura ambiente, deséchela después de 7 días.
- Efectos secundarios: Puede ocurrir malestar estomacal leve (vómitos, diarrea o disminución del apetito). Si estos signos son graves o persisten, comuníquese con su veterinario.
- Reacciones alérgicas: Esté atento a signos de reacción alérgica, como hinchazón facial, urticaria, erupciones cutáneas o dificultad para respirar. Busque atención veterinaria inmediata si ocurren estos síntomas.
- Finalización del tratamiento: Complete siempre la receta completa según las indicaciones, incluso si su mascota parece sentirse mejor, para prevenir el desarrollo de bacterias resistentes.
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.