Which of the following is a long-acting beta-2 bronchodilator (LABA)?

Salmeterol (Serevent) is indeed classified as a long-acting beta-2 bronchodilator (LABA). LABAs are designed to provide prolonged relief from asthma and chronic obstructive pulmonary disease (COPD) symptoms by relaxing the airway muscles. They typically have a duration of action of 12 hours or more, making them suitable for twice-daily dosing to maintain bronchodilation and control asthma symptoms.

Salmeterol specifically works by binding to beta-2 adrenergic receptors located in the airway smooth muscle, leading to bronchodilation, which helps alleviate symptoms such as wheezing and shortness of breath. It is important to use LABAs alongside inhaled corticosteroids to enhance asthma control and reduce the risk of exacerbations.

Other choices include medications that serve different purposes: Racemic Epinephrine is a short-acting bronchodilator used primarily in emergency settings, Ipratropium Bromide is an anticholinergic bronchodilator that provides relief of wheezing and shortness of breath but is also not a LABA, and Cromolyn Sodium is a mast cell stabilizer that helps to prevent asthma attacks but does not act as a bronchodilator.