What are short-acting beta-2 agonists and when are they used?

Short-acting beta-2 agonists, or SABAs, like albuterol are rescue medications that rapidly relax bronchial smooth muscle by stimulating beta-2 adrenergic receptors in the airways. Albuterol begins working within 5 minutes, peaks in 30 to 60 minutes, and lasts 4 to 6 hours. SABAs are used for acute bronchospasm and exercise-induced asthma. They do not treat inflammation. Side effects include tachycardia, tremor, and hypokalemia. Using a rescue inhaler more than twice per week suggests uncontrolled asthma requiring a step-up in controller therapy.