Gentamicin

C. diff Risk

Low

Oral Bioavailability

NA

Approximate Cost

$$

Dosing

Adult

Traditional Dosing
1.5-2mg/kg IV q8h

Extended Interval Dosing
5-7mg/kg IV q24h

Use Adjusted Body Weight for obese patients.

Recommend dosing per Pharmacy

General Information

Common Usage

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

Empiric therapy for pyelonephritis. Used synergistically in enterococcal endocarditis.

Drug Monitoring

Laboratory
Monitor creatinine at least 2 times/week. Discontinue if any signs of nephro or ototoxicity.

Extended Interval Dosing: Target trough <1mcg/mL

Traditional Dosing: Peak monitoring poorly supported by literature, but target peak 8-10mcg/mL; trough < 1 mcg/mL only if using >4 days

Note: 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.

Clinical
Baseline and periodic hearing and vestibular function (questioning audiologic testing with prolonged therapy)

Adverse Effects

  • Nephrotoxicity

  • Auditory toxicity

  • Vestibular toxicity

  • Neuromuscular blockade

Major Interactions

Amphotericin, vancomycin, cyclosporin, NSAIDs, contrast- increased nephrotoxicity

Loop diuretics (e.g. furosemide)- increased ototoxicity

Non-depolarizing muscle relaxants may be potentiated

Additional Information

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

Inform patient of risk of ototoxicity to report any symptoms

Pharmacology

Antimicrobial class: Aminoglycoside

Pregnancy category: D

Average serum half life: 2 hours

Biliary penetration: Moderate

CSF penetration: Poor

Lung penetration: Therapeutic

Urine penetration: Therapeutic