Antimicrobials
Gentamicin

Gentamicin

Low
N/A

Spectrum of Activity

General Information

Administration

  • Infuse over 30-120 minutes
  • Penicillins have been shown to inactivate aminoglycosides, so separate dosing if co-administering

Preparation

  • Dilute in 50-200mL of NS or D5W

Compatibility

  • D5W, NS, or LR
  • Empiric (in combination) or targeted therapy for suspected or confirmed gram negative infections.
  • Empiric therapy for pyelonephritis.
  • Used synergistically in enterococcal endocarditis.

Tier 2 Protected Antimicrobial

  • Broad spectrum, but 1st line for common infections, comes with a high risk of poor stewardship if initial workup and follow-up are not in place

Strategies Used:

  1. Appropriate workup initially
  2. Pharmacists audit/de-escalate
  3. Set EBM Duration

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

Hartford Nomogram

  • Obtain Level 6-14 hours after the start of the 1st infusion and plot on nomogram
  • Nomogram for 7mg/kg, if using different dose divide 7 by mg/kg used times level for appropriate level on nomogram
  • If level falls on the line: choose longer regimen
  • If unable to be obtain on nomogram: use traditional dosing

Traditional Dosing

  • Trough level is 0-60min before a dose (usually pre-4th), and peak is 30-60min after dose infused (usually post-3rd).
  • In critically ill patients, consider checking peak level after the 1st dose as volume of distribution and renal function may change rapidly.
  • Monitor creatinine at least 3 times/week. Discontinue if any signs of ototoxicity.
  • Inform patient of risk of ototoxicity and to report any symptoms.

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

Urine penetration: Therapeutic

Lung penetration: Therapeutic

CSF penetration: Poor

Biliary penetration: Moderate