Beta Agonists

This covers the inhaled β-agonists used for bronchodilation. Information on catecholamines and sympathomimetics with activity on β-receptors is covered under adrenergic vasoactives.

Common Features

Pharmacodynamic Effects β-agonists
Resp Bronchodilatation, ↓ HPV causing ↑ shunt and potential ↓ PaO2 if O2 is not co-administered.
CVS HR1 with higher doses), ↓ BP (β2 with lower doses)
GU Tocolytic.
Metabolic Hypokalaemia from β2 stimulation of Na+/K+ ATPase, hyperglycaemia.
Other Potentiates non-depolarising muscle relaxants


Property Salbutamol Salmeterol
Class Synthetic sympathomimetic amine Synthetic sympathomimetic amine
Uses Acute asthma/bronchospasm, hyperkalaemia Nocturnal and exercise-induced asthma
Presentation MDI (100µg), solution at for nebulisation MDI
Route of Administration Inhaled, IV Inhaled
Dosing 1-2 puffs via MDI, 5mg nebulised. as IV infusion.
Onset Rapid Slow
Distribution Low protein binding
Metabolism High first pass hepatic to inactive metabolites, t1/2β 6 hours. Extensive hepatic via CYP3A4
Elimination Urinary elimination of active (30%) drug and inactive metabolites Renal of metabolites


  1. Peck TE, Hill SA. Pharmacology for Anaesthesia and Intensive Care. 4th Ed. Cambridge University Press. 2014.
  2. Smith S, Scarth E, Sasada M. Drugs in Anaesthesia and Intensive Care. 4th Ed. Oxford University Press. 2011.
Last updated 2017-09-07

results matching ""

    No results matching ""