Gentamicin

C. diff Risk

Low

Oral Bioavailability

NA

Approximate Cost

$$

Dosing

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

  • Use ideal body weight for dosing in most cases

  • Use adjusted body weight for obese patients (BMI≥ 30kg/m²)

  • Aminoglycoside dosing & monitoring per pharmacy available. Order in CareConnect.

CrCl > 60 mL/minCrCl 40 - 60 mL/minCrCl 20 - 39 mL/minCrCl < 20 mL/minNOTE5-7 mg/kg IV Q24h 5-7 mg/kg IV Q36h5-7 mg/kg IV Q48hCall pharmacyExtended dosing allows for high peak to MIC ratios potentially improving efficacy and reducing the risk of nephro- and ototoxicity. An extended-interval level drawn between 6-14 hours (after the start of the infusion) is recommended anytime after the first dose. Peak levels are not necessary and trough levels should be undetectable. Call pharmacy for assessment of aminoglycoside levels.

CrCl > 60 mL/minCrCl 40 - 60 mL/minCrCl 20 - 39 mL/minCrCl < 20 mL/minNote1-2 mg/kg/dose IV Q8h-Q12h1.2-1.5 mg/kg/dose IV Q12h-Q24h1.5 mg/kg/dose IV Q24-Q48h1-1.5 mg/kg/dose IV Q48h-Q72hTarget gentamicin levels: PEAK = 5-10 mg/L and TROUGH = < 1 mg/L. Peak levels should be drawn ½ hour following a ½ hour infusion. Trough levels should be obtained prior to the fourth dose of the regimen. Traditional dosing is the preferred method for Gram-positive synergy dosing in infective endocarditis. For patients with CrCl > 60 ml/min for whom synergy dosing is required, recommend 1 mg/kg/dose IV Q8h. Gram-positive synergy PEAK = 3-4 mcg/mL and TROUGH = undetectable.

HDCRRT3 mg/kg IV x1 then 1-3 mg/kg IV Post HD5 mg/kg IV x1 then 3–5 mg/kg IV Q24-48h

Creatinine Clearance >50mL/min/1.73m²Creatinine Clearance 10-50mL/min/1.73m²Creatinine Clearance ≤10mL/min/1.73m²NotesUncomplicated Infection
7 mg/kg/dose Q24H*

Cystic Fibrosis
10mg/kg/dose Q24H*

Hematology/Oncology
6mo - <9yrs: 10 mg/kg/dose Q24H*
9yrs - <12yrs: 8 mg/kg/dose Q24H*
>12yrs: 7 mg/kg/dose Q24H*
Uncomplicated Infection
CrCl 40-59: 7 mg/kg/dose Q36H
CrCl 20-39: 7 mg/kg/dose Q48H

Cystic Fibrosis
10mg/kg/dose Q36H*

Hematology/Oncology
6mo - <9yrs: 10 mg/kg/dose Q36H*
9yrs - <12yrs: 8 mg/kg/dose Q36H*
>12yrs: 7 mg/kg/dose Q36HDo not use extended interval dosing.
Call pharmacy.
Check a gentamicin level 8H (6-14H) after start of infusion of first dose.

Dosing interval (q24H, q36H, or q48H) dependent upon Extended Interval Level and reference to the Extended Interval Dosing Nomogram

NoteCreatinine Clearance >50mL/min/1.73m²Creatinine Clearance 40-50mL/min/1.73m²Creatinine Clearance 20-39mL/min/1.73m²Creatinine Clearance <20mL/min/1.73m²Creatinine Clearance ≤10mL/min/1.73m²Obtain Trough within 30 min before the next dose and Peak 30 min after 30 min infusion.
Goal Peak:
8-10 mcg/mL, synergy 3-4 mcg/mL.
Goal Trough:
<1 mcg/mLUncomplicated Infection
2.5mg/kg/dose Q8H

Cystic Fibrosis
3.3mg/kg/dose Q8H

Synergy
1mg/kg/dose Q8H2.5mg/kg/dose Q12H2.5mg/kg/dose Q24HLoading dose, then monitor levels every 12-24 hours, target: level <1 mcg/mL
Loading dose, then monitor levels every 12-24 hours, target: level <1 mcg/mL

General Information

  • Nephrotoxicity

  • Auditory toxicity

  • Vestibular toxicity

  • Neuromuscular blockade

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)

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

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

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 to report any symptoms

Antimicrobial class: Aminoglycoside

Pregnancy category: D

Average serum half life: 2 hours

Biliary penetration: Moderate

CSF penetration: Poor

Lung penetration: Therapeutic

Urine penetration: Therapeutic

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

Empiric therapy for pyelonephritis. Used synergistically in enterococcal endocarditis.