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Gentamicin

CLASS

  • aminoglycoside

MECHANISM OF ACTION

  • irreversible binding to bacterial ribosomal proteins -> inhibits protein synthesis

INDICATIONS

  • Antimicrobial cover: gram negative rods (including Pseudomonas)

PHARMACEUTICS

  • 80mg/2mL, clear, colourless (also topical, bone cements, bead)

DOSE

  • up to 5mg/kg loading dose, OD (adjust based on renal function), trough level not > 2mcg/mL

PHARMACOKINETICS

  • Administration – IV
  • Distribution – <10% protein bound, small Vd
  • Metabolism – no active metabolites, no metabolism
  • Elimination – entirely by glomerular filtration, t1/2 = 2-3 hrs

ADVERSE EFFECTS

  • ototoxicity
  • renal toxicity
  • prolongation of neuromuscular blockade
  • rashes
  • abnormal LFT’s
  • other uncommon reactions

SUMMARY OF PROS AND CONS (from Australian Therapeutic Guidelines)

Advantages

  • rapid bactericidal activity associated with rapid control of Gram-negative infections, including Pseudomonas aeruginosa
  • generally low rates of resistance among community-associated and healthcare-associated Gram-negative pathogens
  • has a ‘post-antibiotic effect’ (bacterial killing continues for many hours after plasma concentration is undetectable) that allows for effective once-daily therapy with reduced rates of toxicity
  • synergistic killing when combined with cell-wall–active drugs (eg beta lactams, glycopeptides) for enterococcal and streptococcal infections
  • low rate of drug hypersensitivity reactions
  • low rate of C. difficile infection
  • low cost

Disadvantages

  • nephrotoxicity
    • generally reversible; usually associated with prolonged treatment courses (longer than 5 to 7 days) and pre-existing renal impairment
  • vestibular and, less commonly, auditory toxicity
    • generally irreversible; mostly associated with prolonged treatment courses
  • some recently identified Enterobacteriaceae strains exhibit resistance to multiple drug classes, including to aminoglycosides

CCC Pharmacology Series

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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