Aerosols / Inhalers

Short-acting β2-adrenergic agonist (SABA)

Selective β2 agonist → activates Gs → ↑cAMP → bronchial smooth-muscle relaxation. Some β1 cross-reactivity at high doses (tachycardia).

Inhaled quaternary anticholinergic / muscarinic antagonist

Inhaled quaternary ammonium muscarinic antagonist — minimal systemic absorption. Blocks parasympathetic vagal tone in airways → bronchodilation. Synergistic with β2 agonists.

Inhaled non-selective adrenergic agonist (50:50 D + L isomers)

Topical airway α-agonism → mucosal vasoconstriction → reduced edema. β2 effect contributes to bronchodilation. Used to treat upper-airway edema rather than lower-airway bronchospasm.