Albuterol is a medicine used in the treatment of acute asthma exacerbation. It is used in nebulizer form, in which the liquid medicine is converted into a vapor that can be inhaled into the lungs or in a metered dose inhaler. Albuterol also comes in a liquid version to be used as oral medicine, but it is not as effective as those formulations in which it is delivered directly into the lungs. Even in the aerosol, the body only absorbs a small fraction of any dose given by inhalation.
Once in the lungs, albuterol exerts its action by relaxing the smooth muscle that surrounds the airway. In asthma, chronic inflammation triggered most commonly by allergens and respiratory infections narrow the airways, restricting the flow of air and the exchange of oxygen across the lungs' cell membranes. Albuterol helps improve the absorption of oxygen by increasing the diameter of the airways, allowing more airflow.
Albuterol is called an adrenergic beta-2 agonist. This means that it works by activating specific cellular receptor, called beta-2 receptor, on the airways' smooth muscles. When albuterol activates these receptors, it causes smooth muscle relaxation, which then results in dilatation of the bronchioles in the lungs.
Albuterol does not reduce inflammation in the lungs, which is why patients with asthma also need treatment with steroids to reduce the inflammation, and control of allergens to avoid asthma attacks. Albuterol is a quick acting medicine, producing bronchial dilatation within minutes. It is also a short acting beta agonist; its effect lasts about 4 to 6 hours if inhaled. There are long-acting albuterol formulation that can last in the system up to 12 hours.
