Beta agonist drugs by Ray Sahelian, M.D.

A beta-agonist is a bronchodilator medicine that opens the airways by relaxing the muscles around the airways that may tighten during an asthma attack or in COPD. Beta-agonists can be administered by inhalers or orally. They are called "agonists" because they activate the beta-2 receptor on the muscles surrounding the airways. Activation of beta-2 receptors relaxes the muscles surrounding the airways and opens the airways.

Danger of Beta agonist inhaler
The use of beta agonist inhalers, which include drugs such as Proventil (albuterol), for asthma appears to promote the accumulation of immune cells called type 2 T cells. The results reinforce the importance of including anti-inflammatory steroids, note the authors. Findings suggest beta-agonists promote preferential type 2 T-cell accumulation are consistent with clinical findings that continuous beta agonist therapy leads to deterioration of control in some asthmatics.