Beta-agonists are a type of bronchodilator, which is a medication that causes a person's air passages to open up, making breathing easier. Beta-agonists are one of the main treatments for asthma and are the primary treatment used to stop an acute attack once it has started. Most frequently, they are given by inhaler like steroids. However, these problems are uncommon when the medication is used correctly. Beta-agonists are sometimes prescribed to be used either on a daily basis or only if an acute attack happens.
Theophylline is also a bronchodilator which is taken by mouth.
It is used less frequently than some other medications, but is often added as a second or third drug when previous medications have not effectively controlled the asthma. It is also used for small children and other people who cannot use the inhaled medications properly. Cromolyn sodium is a preventive medication which is inhaled and works by preventing part of the allergic irritation which often provokes asthma. Cromolyn sodium is safe for most people and has few side effects. However, it does not relieve symptoms once they have started.