Antimicrobials
Gentamicin

Gentamicin

Low
N/A

Dosing

General Information

Empiric (in combination) or targeted therapy for suspected or confirmed gram negative infections.

Empiric therapy for pyelonephritis.

Used synergistically in enterococcal endocarditis.

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

  • Once daily dosing: Target trough <2 mcg/mL (ideally <1 mcg/mL). No peak level needed
  • 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 0-60min before a dose (usually pre-4th), and peak is 30-60min 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
  • Piperacillin-tazobactam
  • Cyclosporin
  • NSAIDs
  • Contrast

Increased ototoxicity

  • Loop diuretics (e.g. furosemide)

Non-depolarizing muscle relaxants may be potentiated

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.

Antimicrobial class: Aminoglycoside

Pregnancy category: D

Average serum half life: 2 hours

Urine penetration: Therapeutic

Lung penetration: Therapeutic

CSF penetration: Poor

Biliary penetration: Moderate