Antiasthmatics

Mechanisms

Asthma pharmacotherapy acts via two complementary mechanisms - bronchodilation (beta-2 agonists relaxing airway smooth muscle, anticholinergics blocking bronchoconstrictor tone) and anti-inflammatory action (inhaled corticosteroids suppressing the underlying airway inflammation) - with modern guidelines emphasising anti-inflammatory treatment as central to management, not bronchodilators used in isolation
Beta-2 agonists (short- and long-acting) stimulate beta-2 adrenoceptors on airway smooth muscle, activating a cAMP-mediated relaxation pathway - providing rapid symptomatic relief but not addressing the underlying airway inflammation, explaining why regular use of a bronchodilator alone (without inhaled corticosteroid) is now considered inadequate/inappropriate management
Inhaled corticosteroids suppress airway inflammatory cell activity and cytokine production, reducing both symptom frequency and, importantly, exacerbation risk - the mechanistic basis for current guidelines favouring ICS-containing therapy even in mild asthma

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