II. Indications

  1. Gram Negative Infections

III. Mechanism

IV. Precautions

  1. Administer IV dose over 1 hour
  2. Adjust dosing per kinetics if >1-2 days use
  3. Aminoglycosides are associated with risk of Ototoxicity and nephrotoxicity (FDA black box warning)

V. Dosing: Adults and Children

  1. See Bacterial Conjunctivitis
  2. Adult
    1. Gentamicin 3 to 5 mg/kg/day divided every 8 hours IV or IM (FDA approved) OR
    2. Gentamicin 5 to 7 mg/kg/dose IV every 24 hours (off label)
  3. Child (age >1 month old, weight >2 kg)
    1. Gentamicin 2 to 2.5 mg/kg/dose IV or IM every 8 hours (FDA approved) OR
    2. Gentamicin 5 to 7 mg/kg/dose IV every 24 hours (off label)
  4. Obesity
    1. Base dose on average between the Ideal Body Weight and actual weight

VI. Dosing: Infants

  1. See other references for preterm and Low Birth Weight Infants
  2. Term Infant (age <1 week, weight >2 kg)
    1. Gentamicin 2.5 mg/kg/dose IV or IM every 8 hours (FDA approved) OR
    2. Gentamicin 4 mg/kg IV every 24 hours (off-label)
  3. Term Infant (age 8 to 28 days, weight >2 kg)
    1. Gentamicin 2 to 2.5 mg/kg/dose IV or IM every 8 hours (FDA approved) OR
    2. Gentamicin 4 to 5 mg/kg IV every 24 hours (off-label)

VII. Dosing: Intravesical Gentamicin

  1. See Urinary Catheter associated Urinary Tract Infection (CAUTI)
  2. Indications (off label and uncommon use, but is used by urologists in some cases)
    1. Prophylaxis of recurrent Urinary Catheter associated Urinary Tract Infection (CAUTI)
    2. Treatment of CAUTI when systemic Antibiotics carry greater risk (e.g. recurrent C. difficile)
  3. Compounding pharmacy
    1. Prepare Gentamicin 480 mg in 1 Liter Normal Saline (0.48 mg/ml)
    2. Divided into syringes each containing 50 ml solution (28.8 mg Gentamicin/syringe)
    3. Allows patient or their Caregiver to instill individual doses at home
  4. Instill into Bladder and plug or clamp catheter proximally
    1. Patient lies supine for 1 hour
    2. Drain Bladder after 1 hour
  5. Frequency and duration (varies considerably across studies and is not standardized)
    1. Treatment has been with irrigation twice daily for 7 days
    2. Prophylaxis of recurrent CAUTI
      1. Frequency varies from daily to 2-3 times weekly
      2. Duration varies from 2-3 weeks to 3 months, 9 months and 24 months
  6. References
    1. Andretta (2022) Antibiotics 11(10):1335 +PMID: 36289993 [PubMed]
    2. Marei (2021) J Pediatr Urol 17(1):65.e1-65.e11 +PMID: 33309610 [PubMed]
    3. Pietropaolo (2018) Curr Urol Rep 19(10):78 +PMID: 30094687 [PubMed]
    4. Stalenhoef (2019) J Urol 201(3):549-55 +PMID: 30316898 [PubMed]

VIII. Pharmacokinetics

  1. Target levels for multiple daily dosing
    1. Maintain Trough <2 mcg/ml
      1. Drawn immediately before next dose
    2. Maintain Peak at 5 to 8 mcg/ml in adults (4 to 6 mcg/ml for child)
      1. Draw 1 hour after Intramuscular dose
  2. Target levels for once daily dosing
    1. Maintain peak level 15 to 20 mcg/ml
    2. Maintain trough level <1 mcg/ml
  3. Indications for drug levels followed by Pharmacist
    1. See Aminoglycoside for Nephrotoxicity Risk factors
    2. Aminoglycoside use over 3 days
    3. Renal dysfunction
    4. Burn Injury

IX. Adverse Effects

  1. See Aminoglycoside
  2. Aminoglycosides are associated with risk of Ototoxicity and nephrotoxicity (FDA black box warning)
    1. See Aminoglycoside for risk factors

X. Safety

  1. Pregnancy Category D
  2. Considered safe in Lactation

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Related Studies

Cost: Medications

gentamicin (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
GENTAMICIN 0.1% CREAM Generic $1.07 per gram
GENTAMICIN 0.1% OINTMENT Generic $1.22 per gram
GENTAMICIN 0.3% EYE DROP Generic $0.72 per ml