What Are Beta-Agonists for Asthma?
Albuterol (Ventolin, Proventil), formoterol (Foradil), levalbuterol (Xopenex), metaproterenol (Alupent, Metaprel), pirbuterol (Maxair), and salmeterol (Serevent) are used to decrease bronchospasm. These medications work by stimulating the relaxation of tiny muscles in the airways.
Some long-acting (>12 hours) beta-agonists (for example, formoterol and salmeterol) are specifically designed to prevent asthma attacks and not to treat acute attacks. Other beta-agonists have a quicker onset and may be used for prevention (along with corticosteroid inhalers) and as rescue therapy. Beta-agonists are also useful to use before exercise for exercise-induced asthma.
How beta-agonists work
These drugs relax muscles within the airway that cause bronchospasm. Beta-agonists also cause the airway passages to open wider, thus making breathing easier.
Who should not use these medications
Individuals who are allergic to beta-agonists should not take these drugs.
Both handheld inhalers and a solution for use with a nebulizer are available. Many inhaled products have specific devices and you should be thoroughly informed on how to use the inhaler or nebulizer prescribed for you. Frequency of administration depends on the specific product.
Drug or food interactions
Inhaled anticholinergic medications, such as ipratropium (Atrovent), enhance beta-agonists' effectiveness.
Beta-agonists may cause rapid heartbeat and tremor (shakiness). Individuals with heart disease, hyperthyroidism, seizure disorders, or hypertension should be closely monitored by their doctor. There is a box warning from the FDA on all long-acting beta-agonists stating that there is an increased risk of death when taking these medications. This data is based on a study in asthmatic patients taking long-acting beta-agonists alone. This warning is seen on all FDA-approved medications that include long-acting beta-agonists, such as those used in combination therapy. There is no data demonstrating that taking a long-acting beta-agonist along with other medications such as steroids used in many combination products has any increased risk of death.
Commonly, long-acting beta-agonist therapy and inhaled corticosteroids are used together. These drugs work so that the effectiveness of each component can by enhanced when the other agent is given simultaneously. Combining these agents into a single delivery system also enhances compliance and simplifies care. The two current available brands of combination therapy are Advair (fluticasone and salmeterol), Breo (fluticasone and vilanterol), which uses a powder form of the medications, and Symbicort (budesonide and formoterol) in an inhaler device that includes a propellant. These combination medications come in different strengths. The strength pertains only to the inhaled corticosteroid component. The long-acting beta-agonist dose does not change. Side effects are the same, as noted under the individual components discussed above. The point is that taking an increased number of doses of these combination medications would result in excessive intake of long-acting beta-agonists, and this could be potentially dangerous.