Phenylephrine
CLASS
- synthetic alpha 1 adrenoreceptor agonist
MECHANISM OF ACTION
- alpha 1 agonist
PHARMACEUTICS
- clear, colourless, 10mg/mL -> dilution
- To use as push dose pressor:
— Take a 3 ml syringe and draw up 1 ml of phenylephrine from the vial (vial contains phenylephrine 10 mg/ml)
— Inject this into a 100 ml bag of NS
— Now you have 100 mls of phenylephrine 100 mcg/ml
— Draw up some into a syringe; each ml in the syringe is 100 mcg
Dose
- 0.1-2mcg/kg/min (onset: minutes, duration: up to ~20 minutes)
- 0.5-2 ml every 2-5 minutes (50-200 mcg)
INDICATIONS
- vasodilatory hypotension (e.g. due to induction agents or general anaesthesia — in Australia metaraminol is more commonly used instead)
- nasal decongestant
- mydriasis
- prolong duration of a spinal
ADVERSE EFFECTS
- less potent that noradrenaline
- decrease in HR
PHARMACOKINETICS
- Absorption – IV
- Distribution
- Metabolism – not well described
- Elimination
EVIDENCE
- ANZCA Obstetric Guideline (2008)
-> some data that produces less fetal acidosis in Obstetric Anaesthesia (? significance)
References and Links
- EMCrit Podcast 6 – Push-Dose Pressors
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.
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