What emergency drug is commonly used for an asthma attack?

Salbutamol is the emergency drug commonly used for an asthma attack because it is a bronchodilator that quickly relaxes the muscles in the airways, allowing for easier breathing. It works by targeting beta-2 adrenergic receptors in the lungs, which leads to the dilation of bronchial passages. This is particularly important during an asthma attack when the airways are constricted due to inflammation or spasms.

In contrast, while adrenaline can be used in severe cases of anaphylaxis or severe asthma exacerbations, it is not the first-line treatment for typical asthma attacks. Hydrocortisone is a corticosteroid that may be used in chronic management or severe cases but does not provide immediate relief. Atropine is an anticholinergic drug typically not indicated for asthma treatment. Therefore, salbutamol is the most effective and commonly used medication for immediate relief during an asthma attack.