Antimicrobials
Gentamicin

Gentamicin

Spectrum of Activity

General Information

5-8 mg/kg IV/IM/SQ q24h

9-12 mg/kg IV/IM/SC q24h

CLSI breakpoint for Enterobacterales and Pseudomonas based on 10 mg/kg IM q24h

  • Mainly used for infections caused by Gram negative pathogens
  • Occasionally used for staphylococcal infections
  • Amikacin is preferred because of reduced risk of toxicity

Monitoring

  • Evaluate urine specific gravity and serum creatinine prior to treatment and periodically during treatment (e.g. every 3-5 days)
  • Cytological examination of urine for casts should be considered concurrently
  • Monitoring peak and trough drug levels is ideal, when available
  • Concentration-dependent
  • IV, IM, and SC routes of administration
  • Does not cross the placenta of late term mares
  • Distributed primarily in the extracellular fluid
    • Local inflammation may increase drug concentrations in joints
  • Eliminated by glomerular filtration
  • Half-life: 1-3 hours for adult animals
    • Increased in neonates and animals with renal dysfunction
  • Nephrotoxicity
  • Vestibulocochlear toxicity
  • Neuromuscular blockade
  • Halothane anesthesia causes significant changes in pharmacokinetics in horses
  • Avoid concurrent use with:
    • Nephrotoxic drugs
    • Neuromuscular blocking agents
    • Diuretics
  • Synergistic activity with ß-lactam antibiotics

No approved parenteral products for dogs and cats in Canada.

Cats may be more sensitive to toxic effects.

  • Giguère S, Prescott JF, Dowling PM, Eds. Antimicrobial Therapy in Veterinary Medicine. 5th ed. Wiley Blackwell; 2013.
  • Plumb DC. Gentamicin. Plumb’s Veterinary Drugs. Updated July 2018.