The Asthma Center

β2-Agonists (bronchodilators)


ß2-agonists are very similar to epinephrine medications. By selectively stimulating ß2 (beta-2) receptors, these preparations relax your spastic or constricted airways. The major advantage of these medications over synthetic epinephrine is that they primarily stimulate the bronchial tubes (via ß2 receptors). These medications also cause much less stimulation to the heart and to the blood vessels. ß2-agonists (beta-2 stimulators) include:

  • metaproterenol (Alupent®)
  • albuterol (AccuNeb®, Proventil®, Ventolin®, Xopenex®), terbutaline (Brethine®, Bricanyl®), and pirbuterol (Maxair™ Autohaler™)
  • salmeterol (Serevent®) and formoterol (Foradil®) are long acting; formoterol (Foradil®) has a faster onset than salmeterol (Serevent®)

The latter two groups are more selective bronchodilators than metaproterenol and have less effect on the heart. Tremors may still occur with these medications, but they may subside with time.


Although some of these medications are available as injections (terbutaline), The Asthma Center specialists usually recommend administration of ß2-agonist medications by inhalation (MDI or DPI). Occasionally the liquid or tablet forms of these medications are recommended when an inhaler or nebulizer cannot be used effectively. A spacer device or holding chamber is often used with a metered-dose inhaler for better delivery.

Please note: Serevent® and Foradil® should not be used more than twice a day since they are long acting. Therefore the use of a short acting bronchodilator (NOT Serevent® or Foradil®) is recommended to treat a sudden onset of asthmatic symptoms.

Risks and Precautions

Side effects from these medications include:

  • Palpitations (racing or pounding heartbeat)
  • Headache
  • Nausea
  • Irritability


Overuse of these medications (inhaler abuse) is extremely dangerous and a sign of poor asthma management.

Extreme inhaler overuse may lead to false confidence due to a limited short term relief while, in fact, your asthmatic state gradually worsens and your risk of heart toxicity from the medication increases. If you use your ß2-agonist inhaler this way, you may no longer respond to the inhaler and may suddenly develop severe respiratory distress. Such a situation can result in death in spite of emergency treatment. Overuse of ß2-agonist metered-dose inhalers usually means that you have put off appropriate treatment for too long. If you use this type of inhaler more than 5 - 6 times per day or on average more than one inhaler per month, you should discuss your asthma management with your physician.

These bronchodilators have little or no anti-inflammatory activity. Therefore, they offer only temporary relief from symptoms and do not correct the underlying problem of inflammation. Use of a ß2-agonist more than 3 times a week indicates the need for an anti-inflammatory controller medication.