Asthma Mechanism
As the Mayo Clinic explains, an asthma attack is caused by the airways becoming swollen and inflamed. One of the causes behind this is constriction of the smooth muscles that surround the lower portion of the airway (also known as the bronchioles). The narrowed airways make it harder to breath and can also cause wheezing. Because asthma is a chronic disease it can be difficult to cure. Many treatments, including albuterol, work to either prevent acute flareups or to ease the symptoms of an asthma attack.
Albuterol Pharmacology
Smooth muscle (including the tissue around the airways) is controlled by the autonomic nervous system. The autonomic nervous system is responsible for involuntary muscle contractions and movements. The autonomic nervous system controls smooth muscles through special proteins called receptors, which signal for the smooth muscle to contract or relax. According to RXList, Albuterol works by binding to some of the receptors on the smooth muscle cells called beta adrenergic receptors. When albuterol binds to these receptors, it sends a signal into the smooth muscle cells, telling them to take in less calcium. Because calcium causes muscle cells to contract, this causes the smooth muscle cells to relax, which allows the airways to expand.
Administration
Albuterol can be inhaled or taken orally. The inhaled form is often given using a "rescue inhaler." Rescue inhalers release a small dose of albuterol in aerosol form so that it can be inhaled. This allows it to act quickly and directly on the smooth muscles in the airways. Rescue inhalers are often used during an asthma attack for immediate relief. Albuterol can also be taken orally, for long-term relaxation of the smooth muscle cells. When albuterol is taken orally, it is typically used to reduce the frequency of asthma attacks.
