Penicilina G
Penicillin G
Benzylpenicillin
También conocido como: Bicillin C-R · Masti-Clear · Permapen · Pfizerpen · Go-Dry · crystalline penicillin G · APPG · aqueous penicillin · procaine benzylpenicillin
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): Penicillin G procaine
Requiere verificación veterinaria
- q12-24h
NA
Contexto clínico obligatorio (4)
- NOTE: Label dosages of penicillin have been unchanged for decades and may result in marked underdosing based on current understanding of antibiotic therapy. Although consideration of the label recommendations is required, present-day recommended dosing regimens should be used.
- ■ Because penicillins usually have minimal toxicity associated with their use, monitoring for efficacy is usually all that is required unless toxic signs develop. Serum concentrations and therapeutic drug monitoring are not routinely done with these agents.
- Penicillin G procaine should be stored at 2°C to 8°C (36°F-46°F); avoid freezing. Penicillin G benzathine should be stored at 2°C to 8°C (36°F-46°F).
- Penicillin G sodium and potassium powder for injection can be stored at room temperature (15°C-30°C [59°F-86°F]). After reconstituting, the injectable solution is stable for 7 days when kept refrigerated (2°C-8°C [36°F-46°F]) and for 24 hours at room temperature.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
La Penicilina G (bencilpenicilina) es un antibiótico betalactámico natural de espectro reducido derivado del Penicillium chrysogenum. Es altamente eficaz contra la mayoría de las bacterias aerobias Gram-positivas (p. ej., Streptococcus spp., Staphylococcus que no producen penicilinasa), algunas bacterias Gram-negativas (p. ej., Pasteurella) y muchas bacterias anaerobias (p. ej., Clostridium spp.).
Perla clínica: La forma de sal de la Penicilina G determina su vía de administración y perfil farmacocinético:
- Sales acuosas (Sódica o Potásica): Formuladas para uso IV o IM. Proporcionan concentraciones séricas máximas rápidas y elevadas, pero tienen una vida media muy corta, lo que requiere una dosificación frecuente (p. ej., q4-6h).
- Sales de depósito (Procaína y Benzatina): Formuladas como suspensiones para uso IM o SC ÚNICAMENTE (nunca IV). La procaína proporciona un efecto de depósito que dura 12-24 horas, mientras que la benzatina proporciona concentraciones muy bajas y prolongadas que duran varios días.
La Penicilina G es susceptible a la degradación por enzimas betalactamasas (penicilinasas) producidas por muchos Staphylococci y bacterias entéricas Gram-negativas.
Mecanismo de acción
Penicillin G is a time-dependent bactericidal antibiotic.
- It covalently binds to Penicillin-Binding Proteins (PBPs) located on the inner membrane of the bacterial cell wall.
- This binding → inhibits the transpeptidation enzyme responsible for cross-linking peptidoglycan strands.
- Failure of cell wall synthesis → activation of autolytic enzymes within the cell wall → osmotic lysis and bacterial death.
Because it targets cell wall synthesis, it is most effective against actively dividing bacteria.
Seguridad y advertencias
Contraindicaciones
- Known hypersensitivity to penicillins or cephalosporins
- Intravenous administration of Procaine or Benzathine suspension formulations
- Oral administration in horses and hindgut fermenters (rabbits, guinea pigs) due to risk of fatal dysbiosis (unless specifically indicated, e.g., calves with clostridial enteritis)
Efectos adversos
- Hypersensitivity reactions (anaphylaxis, urticaria, rash)
- Gastrointestinal upset (anorexia, vomiting, diarrhea) with oral use
- Procaine toxicity (CNS excitement, seizures) in small birds and horses if inadvertently given IV
- Pain or tissue reaction at IM injection sites
Precauciones
Use cautiously in small birds as procaine penicillin may cause procaine toxicity. Do not use oral penicillin therapy in horses for systemic infections (e.g., botulism). Ensure repository forms (procaine/benzathine) are never administered intravenously. Monitor for hypersensitivity reactions. High doses of Penicillin G Potassium given rapidly IV can cause hyperkalemia and cardiac arrhythmias.
Interacciones farmacológicas
May antagonize the bactericidal activity of penicillins, which require actively dividing cells to be effective.
In vivo synergy against certain bacteria; however, physically incompatible if mixed in the same syringe or IV line (inactivation of the aminoglycoside).
Competitively inhibits renal tubular secretion of penicillins, significantly prolonging their half-life and increasing serum concentrations.
Monitorización
- Clinical efficacy (resolution of infection signs)
- Signs of toxicity or hypersensitivity (anaphylaxis, rash)
- Electrolytes (if using high doses of Na or K salts IV)
Farmacocinética
Vida media
Absorción
Oral absorption is generally poor and variable due to degradation by gastric acid. Aqueous salts (Na/K) are rapidly absorbed after IM/SC injection. Procaine and benzathine salts are slowly absorbed from IM injection sites, providing prolonged but lower serum concentrations.
Distribución
Widely distributed to most tissues (lungs, kidneys, muscle, bone). Poor penetration into the central nervous system (CNS), eye, and prostate unless severe inflammation is present. Crosses the placenta.
Metabolismo
Minimal hepatic metabolism.
Eliminación
Rapidly excreted primarily unchanged in the urine via active renal tubular secretion and glomerular filtration.
Sobredosis
Because penicillins usually have minimal toxicity associated with their use, monitoring for efficacy is usually all that is required unless toxic signs develop.
Clinical Pearl: Massive overdoses, particularly of aqueous salts given rapidly IV, can lead to neuromuscular hypersensitivity, seizures, or electrolyte imbalances (hyperkalemia with potassium salt, hypernatremia with sodium salt). Treatment is supportive.
Productos disponibles
Formulaciones
- Powder for injection (Potassium or Sodium salts)
- Suspension for injection (Procaine or Benzathine salts)
- Oral tablets and powder for solution
- Intramammary infusion syringes
Veterinario
- Penicillin G Procaine Injection 300,000 Units/mL
- Penicillin G Procaine Mastitis Syringes 100,000 Units/mL (Go-Dry, Masti-Clear)
- Penicillin G Benzathine 150,000 Units/mL with Penicillin G Procaine 150,000 Units/mL Injection
Etiquetado para humanos
- Penicillin G (Aqueous) Sodium Powder for Injection: 5,000,000 Units & 20,000,000 Units
- Penicillin G (Aqueous) Potassium Injection: 1,000,000 Units, 2,000,000 Units & 3,000,000 Units
- Penicillin G Procaine Injection: 600,000 Units/vial & 1,200,000 Units/vial
- Penicillin G Benzathine Injection: 600,000, 1,200,000, & 2,400,000 Units/dose
- Penicillin G Benzathine/Penicillin G Procaine IM Injection (Bicillin C-R)
Estado regulador
Sin datos reguladores para: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Penicillin G sodium and potassium powders should be protected from moisture. Oral powder for solution: store at room temperature before mixing; after reconstituting, refrigerate (2-8°C) and discard after 14 days. Injectable Na/K solutions: stable for 7 days refrigerated (2-8°C) and 24 hours at room temperature. Procaine and Benzathine suspensions should be stored at 2-8°C; avoid freezing.
Información para el cliente
- Administración: Administre las penicilinas orales con el estómago vacío (1 hora antes o 2 horas después de una comida) para maximizar la absorción. Si su mascota presenta malestar estomacal (vómitos, pérdida de apetito), puede administrarla con una pequeña cantidad de comida.
- Cumplimiento: Es fundamental completar toda la prescripción exactamente como se indica, incluso si su mascota parece estar completamente recuperada. Suspender el tratamiento antes de tiempo puede provocar infecciones resistentes.
- Reacciones alérgicas: Esté atento a signos de reacción alérgica, como hinchazón facial, urticaria, erupciones cutáneas o dificultad para respirar. Comuníquese con su veterinario de inmediato si esto ocurre.
- Sitios de inyección: Si su mascota está recibiendo formas inyectables, el sitio de la inyección puede volverse doloroso o inflamarse.
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.