Antimicrobials
Penicillin G sodium/potassium

Penicillin G sodium/potassium

Spectrum of Activity

General Information

20,000-40,000 IU/kg IV q4-8h

20,000-40,000 IU/kg IV q4-8h

Sodium penicillin for injection

  • 1 million IU vial
  • 5 million IU vial
  • 10 million IU vial
  • Rarely used as it is narrow spectrum and requires injection
  • Ampicillin sodium is most often used for intravenous Gram positive coverage
  • Natural penicillin
  • Bactericidal, time-dependent
  • This formulation is water soluble and can be injected IV, IM, or SC
    • Rapidly absorbed
  • Poor absorption with oral administration
  • Widely distributed (with the exception of CSF, joints, and milk)
  • Excreted unchanged in urine
  • Hypersensitivity reactions
  • GI upset
  • Neurotoxicity (with high doses and prolonged use)
  • May cause electrolyte imbalances in small animals with preexisting abnormalities, renal diseases, or congestive heart failure
  • Should not be administered with bacteriostatic antimicrobials
  • Can have synergistic activity when used with aminoglycosides

No approved veterinary products for dogs and cats in Canada.

Also known as benzylpenicillin sodium, aqueous or crystalline penicillin.

Can be administered IV.

  • Giguère S, Prescott JF, Dowling PM, Eds. Antimicrobial Therapy in Veterinary Medicine. 5th ed. Wiley Blackwell; 2013.
  • Plumb DC. Penicillin G. Plumb’s Veterinary Drugs. Updated September 2017.