Co-trimoxazole

CLASS

  • 2 antibiotics (sulfamethoxazole and trimethoprim)

MECHANISM OF ACTION

  • sulfamethoxazole -> inhibits bacterial synthesis of dihydrofolic acid
  • trimethoprim -> blocks production of tetrahydrofolic acid

-> blocks two consecutive steps in the biosythesis of nucleic acids and proteins essential to bacteria.

PHARMACEUTICS

  • PO – each tablet = 80mg trimethoprim and 400mg sulfamethoxazole
  • IV – 5mL contains 80mg trimethoprim and 400mg sulfamethoxazole (referred to as 480mg, requires appropriate dilution in to a large volume of fluid)

DOSE

  • IV: 960-1440mg/day in divided doses, for PCP use 120mg/kg in divided doses Q6hrly for 14 days
  • PO: for PCP prophylaxis 960-1920mg on alternate days

INDICATIONS

  • PCP (infection and prophylaxis)
  • Stenotrophomonas and other multi-drug resistant infections (e.g. MRSA skin infections)
  • Nocardia
  • Toxoplasmosis
  • Gram positive cocci
  • Gram negative bacilli (Pseudomonas, xanthomonas)

CONTRAINDICATIONS

  • hypersensitivity
  • blood dyscrasia
  • marked renal or hepatic impairment
  • megaloblastic bone marrow

ADVERSE EFFECTS

  • photosensitivity
  • superinfection (pseudomembranous colitis)
  • GI upset
  • CNS effects
  • interactions: diuretics -> thrombocytopaenia, warfarin -> increase INR
  • haematological effects

PHARMACOKINETICS

  • Absorption
  • Distribution
  • Metabolism
  • Elimination

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and 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 two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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