Describe the mechanism of action of drugs commonly used to treat acute severe asthma.

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College Answer

Answers to this question needed to address drugs that target the pathophysiology of 
asthma: bronchospasm, inflammation (oedema and hypersecretion), and hyperreactivity to inhaled stimuli. Not all drugs used to treat less severe forms of the 
disease are relevant in the critical care context.
A discussion of efficacy versus toxicity was included in better answers. 
As a minimum, sympathomimetics, antimuscarinics, corticosteroids and 
methylxanthines should have been included. The role of inhaled Adrenaline as a B2
-agonist mediating bronchodilatation and an alpha-agonist constricting the bronchial 
mucosa was relevant to the discussion. Ketamine and volatile anaesthetics could 
have been discussed as adjuncts to therapy in ventilated patients. More 
controversial therapies such as Magnesium and Heliox are less commonly 
prescribed, however marks were awarded for more comprehensive answers.
Syllabus B2a 2a
Reference: Goodman and Gilman's the Pharmacological Basis of Therapeutics 11th
Ed p717-736