Gentamicin

Gentamicin

[1 amp 62 cents]

ADMINISTRATION ROUTES:

  • IV, IM

ALTERNATIVE NAMES:

  • Gentamicin

ICU INDICATIONS:

  1. Treatment of infection scaused by susceptible organisms
  2. Antibiotic synergism for infections caused by Pseudomonas, Acinetobacter and Enterobacteriaceae

PRESENTATION AND ADMINISTRATION:

  • IV Use:
    80mg in 2ml
    Add required dose to 100ml of compatible IV fluid and administer over 30 minutes
    Dilutions in compatible IV fluid should be prepared immediately before use and any solution not used within 24 hours should be discarded
    Store at room temperature
  • IM:
    Not recommended by this route in ICU

DOSAGE:

  • 5-7mg/kg once daily (monitor levels)

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose in renal impairment [GFR (ml/min)]
    <10: 2 mg/kg 48 hourly and measure levels
    >10-20: 3 mg/kg 48 hourly and measure levels
    >20-30: 4 mg/kg 48 hourly and measure levels
    >30-40: 2.5mg/kg 24 hourly and measure levels
    >40-60: 3.5mg/kg 24 hourly and measure levels
    >60-80: 4mg/kg 24 hourly and measure levels
  • Dose in renal replacement therapy
    CAPD: 2 mg/kg 48 hourly and measure levels
    HD: 2 mg/kg post dialysis and measure levels
    CVVHDF: 4 mg/kg 48 hourly and measure levels

DOSAGE IN PAEDIATRICS: 5-7mg/kg daily

CLINICAL PHARMACOLOGY:

  • In vitro tests have demonstrated that gentamicin is a bactericidal antibiotic which acts by inhibiting normal protein synthesis in susceptible microorganisms.
  • It is active against a wide variety of pathogenic bacteria including:
    Escherichia coli, Proteus species (indole-positive and indole-negative), Pseudomonas aeruginosa, species of the Klebsiella-Enterobacter-Serratia group, Citrobacter species, and Staphylococcus species (including penicillin- and methicillin-resistant strains).
    Gentamicin is also active in vitro against species of Salmonella and Shigella.
  • The following bacteria are usually resistant to aminoglycosides:
    Streptococcus pneumoniae, most species of streptococci, particularly group D and anaerobic organisms, such as Bacteroides species or Clostridium species.

CONTRAINDICATIONS:

  1. hypersensitivity to gentamicin or other aminoglycosides

WARNINGS

  • Nephrotoxicity:
    As with other aminoglycosides, gentamicin is potentially nephrotoxic. The risk of nephrotoxicity is greater in patients with impaired renal function and in those who receive high dosage or prolonged therapy.
  • Ototoxicity:
    Neurotoxicity manifested by ototoxicity, both vestibular and auditory, can occur in patients treated with gentamicin, primarily in those with pre-existing renal damage and in patients with normal renal function treated with higher doses and/or for longer periods than recommended; however, it may occur in the absence of these risk factors. Aminoglycoside-induced etotoxicity is usually irreversible.

PRECAUTIONS

  • General:
    Gentamicin sulfate contains sodium bisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. Aminoglycosides should be used with caution in patients with neuromuscular disorders, such as myasthenia gravis, since these drugs may aggravate muscle weakness because of their potential curare-like effects on the neuromuscular junction.
  • Laboratory Tests:
    Monitor gentamicin levels: Collect trough specimens in a Plain (Red) or SST (Yellow) Tube. For Paediatric and Neonatal patients use a 0.4 mL green microtainer
  • Drug/Laboratory Test Interactions:
    None reported

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • Concurrent and/or sequential use of other potentially neurotoxic and/or nephrotoxic drugs, such as cisplatin, amikacin, neomycin, polymyxin B, colistin, and vancomycin, should be avoided.
  • The concurrent use of gentamicin with potent diuretics, such as frusemide, should be avoided, since certain diuretics by themselves may cause ototoxicity. In addition, when administered intravenously, diuretics may enhance aminoglycoside toxicity by altering the antibiotic concentration in serum and tissue.

ADVERSE REACTIONS

  • Body as a Whole:
    lethargy, urticaria, generalised burning, anaphylactoid reactions
  • Nervous System:
    Ototoxicity, headache, confusion, visual disturbances
  • Renal System:
    Renal failure
  • Respiratory System:
    Respiratory depression, laryngeal oedema
  • Cardiovascular System:
    Hypotension and hypertension
  • Gastrointestinal System:
    Decreased appetite, nausea, vomiting, increased salivation, hepatitis, cholestasis and stomatitis
  • Haematological System:
    Anaemia, leukopenia, granulocytopenia, transient agranulocytosis, eosinophilia, increased and decreased reticulocyte counts, and thrombocytopenia.

Critical Care Drug Manual

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