Salbutamol is a short-acting β2-adrenergic receptor agonist that works by relaxing the bronchial smooth muscle. This leads to bronchodilation, which helps relieve bronchospasm commonly seen in patients with bronchial asthma. It is primarily used as a rescue medication to quickly alleviate symptoms such as wheezing, breathlessness, and chest tightness during asthma attacks. It does not treat the underlying inflammation but provides rapid symptomatic relief. Salbutamol is not indicated for hypertension, diabetes mellitus, or peptic ulcers, as its mechanism targets airway smooth muscle specifically.

Reference: Goodman & Gilman's The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.