Pharm 101: Adrenaline

Class

Endogenous catecholamine
Vasopressor

Pharmacodynamics
  • Alpha and beta agonist
    • Beta 1 = positive inotropy and chronotropy
    • Alpha = vasoconstriction
    • Beta 2 = skeletal muscle vasodilation, may explain decreased DBP sometimes seen
  • Non-selective adrenergic agonist:
    • Potent beta-1 receptor activity causes positive inotropy and chronotropy
    • Moderate alpha-1 receptor activity causes peripheral vasoconstriction and increases SVR
    • Moderate beta-2 receptor activity causes skeletal muscle vasodilation (may explain decreased DBP sometimes seen), and relaxes bronchial smooth muscle and stabilises mast cells
Pharmacokinetics
  • IV/IM/ETT/SC administration
  • Onset of action 1-2 minutes
  • Half-life 5 minutes
  • Duration of action 2-10 minutes
  • Metabolised by MAO and COMT to VMA and metadrenaline
  • Urinary excretin of metabolites
Clinical uses
  • To increase CO/HR, MAP and coronary blood flow
  • Septic shock:
    • In addition to noradrenaline (first line agent) to raise MAP
  • Cardiac arrest
  • Anaphylaxis
  • Bronchospasm causing respiratory distress
  • Infusion (central):
    • 6mg adrenaline in 100ml 5% dextrose (final concentration 60 microg/ml)
    • 1ml/hr = 1 microg/min
    • Starting dose: 1-4 microg/min, titrate to BP
    • Usual dose range: 1-20 microg/min
Adverse effects
  • Angina, tachycardia, arrhythmias and palpitations
  • Tissue ischaemia or necrosis due to vasoconstriction
  • Hyperglycaemia
  • Lactic acidosis
Precautions/contraindications
  • Hypotension due to uncorrected hypovolaemia
  • Tachycardia and arrhythmias
  • Hypersensitivity to sulphites
  • Wean gradually to avoid hypotension
Further reading
References
  • Katzung BG. Basic & Clinical Pharmacology. 14e. 2018: 96-97
  • Better Safe Care. Melbourne, Australia: Victorian Agency for Health Information; 2018. Adrenaline (epinephrine). 2019 May 07 [cited 2020 Aug 02].
Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS CCPU (RCE, Biliary, DVT, E-FAST, AAA) Rob is an Emergency Medicine Advanced Trainee based in Melbourne, Australia. He has special interests in medical education, ECG interpretation, and the use of diagnostic and procedural ultrasound in the undifferentiated and unwell patient.

Follow him on twitter: @rob_buttner | ECG Library |

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.