Selected Antimicrobial Information – Equine
Penicillin [Equine]
Restriction Status
Unrestricted
Dose
| Species | Usage | Dose |
|---|---|---|
| Horses |
For susceptible infections (Sodium penicillin G, potassium penicillin G) | 22,000-44,000 IU/kg IV q6h, given slowly |
| For susceptible infections (Procaine penicillin G) | 22,000 IU/kg IM q12h |
Brand Name(s)
sodium penicillin G, potassium penicillin G, procaine penicillin G; penicillin V potassium
Background
Penicillin G is a bactericidal, time-dependent β-lactam antibiotic with good activity against many Gram-positive organisms, though it is not effective against β-lactamase-producing Staphylococcus spp., α-Streptococcus spp., or Rhodococcus equi. It has limited efficacy against Gram-negative bacteria. Penicillin G distributes widely through the plasma but has low lipid solubility and does not penetrate abscesses or sites of tissue necrosis well. The active form of penicillin G is excreted in high concentration in the urine.
Acceptable Uses
- First line choice for treatment of streptococcal infections such as Streptococcus equi (strangles), or Streptococcus zooepidemicus (upper and lower respiratory infection).
- Treatment of clostridial infections such as clostridial myositis, botulism, or tetanus.
- Treatment of susceptible urinary tract infections.
- When used in combination with gentamicin, a first line choice for broad-spectrum therapy (as in cases of peritonitis, pleuropneumonia, cholangiohepatitis, sepsis, or endocarditis).
- Treatment of orthopedic infections (osteomyelitis, septic arthritis) when β-lactamase-producing Staphylococcus spp. or Enterobacteriaceae have been ruled out by culture.
Unacceptable Uses
- Treatment of suspected or cultured-confirmed Enterobacteriaceae infections.
- Inactivated in the presence of purulent or necrotic material (e.g. abscesses).
- Empirical treatment of suspected staphylococcal infections.
- In combination with a bacteriostatic antimicrobial, efficacy is decreased.
Formulations Available within the OSU Pharmacy
- Penicillin gel 5ml/syringe
- Penicillin gel 10ml/syringe
- Penicillin G Potassium 20mmu injectable suspension
- Penicillin G Procaine injectable suspension (1 ml, 30 ml, 100 ml, 250 ml)
Notes
- Intravascular injection of procaine penicillin G can cause excitement, seizure-like activity, and death. Procaine penicillin G should be given IM only.
- Rapid IV administration of potassium penicillin can cause head shaking/lip smacking, salivation, lacrimation, increased borborygmi, colic, agitation, and soft to liquid feces. Potassium penicillin should be given over 5 minutes.
