title: Indication
    
  Treatment of gram-negative infections.
      
  Action
text: Indication
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  Treatment of gram-negative infections.
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  Action
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  Bactericidal agent that acts by inhibiting protein synthesis in susceptible bacteria.
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  Drug type
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  Aminoglycoside antibiotic
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  Trade name
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  DBL gentamicin, Gentamicin BP (Pfizer)
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  Presentation
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  10 mg/mL ampoule – paediatric strength
  80 mg/2 mL ampoule – adult strength
  NOTE: SAS product may be considered in the event of a shortage. Consult the local pharmacy.
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  Dose
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  Dose: 5 mg/kg as follows: (2-5)
  Corrected Gestational Age/Postmenstrual Age*
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  Route
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  Dosing interval
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  Drug concentration to be performed at:
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  < 30+0 weeks*
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  IV/IM
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  48 hourly
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  22 hours after the 2nd dose
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  30+0─34+6 weeks*
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  IV/IM
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  36 hourly
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  22 hours after the 2nd dose
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  ≥ 35+0 weeks*
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  IV/IM
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  24 hourly
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  22 hours after the 2nd dose
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  *Concurrent cyclo-oxygenase inhibitors (indomethacin or ibuprofen) (6-8)
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  IV/IM
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  Extend dosing interval by 12 hours
  Example:
  48 hourly to 60 hourly
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  Therapeutic hypothermia (9-13)
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  IV/IM
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  36 hourly
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  Trough concentrations prior to every dose
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  Subsequent dose interval is based on a gentamicin concentration at 22 hours after the administration of the 2nd dose as indicated in the table below.(3, 4)
  22-hour Gentamicin concentration*
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  Interval
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  ≤ 1.2 mg/L
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  Every 24 hours after previous dose
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  1.3 mg/L ─ 2.6 mg/L
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  Every 36 hours after previous dose
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  2.7 mg/L ─ 3.5 mg/L
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  Every 48 hours after previous dose
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  ≥ 3.6 mg/L
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  Hold dose, repeat concentration 24 hours later
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  *Different to trough concentration performed prior to next dose – Refer to dose adjustment section.
  Gentamicin monitoring is required ONCE only, except when the duration of gentamicin therapy is greater than 7 days or with the conditions described in dose adjustment and monitoring section.
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  Dose adjustment
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  Therapeutic hypothermia –36 hourly interval(9-13). Measure trough concentrations before every dose.
  ECMO - Renal dysfunction is the main determinant. Measure trough concentration before 2nd dose.(14)
  Renal impairment – Measure trough concentration before every dose.
  Hepatic impairment – No specific dose adjustment.
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  Maximum dose
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  Total cumulative dose
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  Route
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  IV
  IM – only if IV access is not available.
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  Preparation
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  10mg/mL – paediatric strength
  Draw up 1mL (10mg) gentamicin and add to 4mL of sodium chloride 0.9% to make a final volume of 5mL with a concentration of 2mg/mL solution.
  80mg/2 mL – adult strength
  Draw up 1mL (40mg) gentamicin and add to 19mL of sodium chloride 0.9% to make a final volume of 20mL with a concentration of 2mg/mL solution.
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  Administration
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  IV - Inject slowly over 5 minutes as an IV injection.(15)
  IM- only given when IV route is not available as the IM absorption is variable. Administer required dose undiluted, deeply into anterolateral thigh muscle.
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  Monitoring
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  Urine output, urine analysis, blood urea, nitrogen and creatinine
  Monitor for anaphylaxis
  Trough concentrations – Target trough concentration: <2 mg/L. Repeat trough concentrations are not required routinely unless: (4)
  duration of therapy is ≥ 7 days – In this scenario, prior to dose on day 7 and then weekly thereafter.
  renal impairment or perinatal hypoxia with Apgar <5 at 5 minutes and/or concomitant use of other nephrotoxic agents or therapeutic hypothermia In these scenarios, perform trough concentration prior to every dose.
  If trough concentration ≥2 mg/L, withhold the dose, repeat trough concentrations before the subsequent dosing and discuss with infectious disease specialist/clinical microbiologist for either extended dosing interval or alternate antibiotic.
  Peak concentrations - Not required routinely. Target peak concentrations: 5-12 mg/L. Peak concentration should be drawn at 30 minutes post dose.
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  5>2> |