Escherichia coli (Gram Negative Bacillus - ICU)
Gentamicin

Gentamicin

Low
N/A

General Information

  • Empiric (in combination) or targeted therapy for suspected or confirmed gram negative infections.
  • Empiric therapy for pyelonephritis.
  • Used synergistically in enterococcal endocarditis.

Black Box Warning:

  • Injection
  • Patients with impaired renal function, advanced age, dehydration, and those who receive high doses or prolonged therapy are at an increased risk of toxicity.
  • Monitor renal and auditory function during therapy and discontinue therapy or adjust dose if there is evidence of ototoxicity or nephrotoxicity.
  • Serum concentrations of aminoglycosides should be monitored when feasible to assure adequate levels and to avoid potentially toxic levels.
  • Concurrent use of other potentially neurotoxic or nephrotoxic agents, or potent diuretics should be avoided.
  • Aminoglycosides can cause fetal harm when administered to a pregnant woman.

Monitor creatinine at least 3 times/week. Discontinue if any signs of ototoxicity.

Once daily dosing: Target trough <1 mcg/mL

Multiple daily dosing: Peak monitoring poorly supported by literature, but target peak 4-10 mcg/mL; trough 1-2 mcg/mL only if using >4 days

NB: Trough level is 0-60 min before a dose (usually pre-4th), and peak is 30-60 min after dose infused (usually post-3rd).

In critically ill patients, check peak level after the 1st dose as volume of distribution and renal function may change rapidly.

Nephrotoxicity (non-oliguric)

  • Avoid concomitant nephrotoxins
  • Less common with once daily dosing
  • Greater toxicity with longer duration and supratherapeutic trough levels

Vestibulocochlear toxicity

  • Irreversible
  • Require audiology testing if prolonged use

Can exacerbate neuromuscular blockade

  • Contraindicated in patients with myasthenia gravis

Increased nephrotoxicity:

  • Amphotericin
  • Vancomycin
  • Cyclosporin
  • NSAIDs
  • Contrast

Increased ototoxicity:

  • Loop diuretics (e.g. Furosemide)

  • Non-depolarizing muscle relaxants may be potentiated

Antimicrobial class: Aminoglycoside

Pregnancy category: D

Average serum half life: 2 hours

Biliary penetration: Moderate

CSF penetration: Poor

Lung penetration: Therapeutic

Urine penetration: Therapeutic

Formal audiology assessment if planning to use aminoglycoside for >7d or if symptoms develop.

Inform patient of risk of ototoxicity and to report any symptoms.