Beta-2 agonists
Beta-2 agonists are available in short-acting and long-acting varieties, and are usually taken through an inhaler.
They relax the muscles in the lungs, which allows the airways to widen. Long-acting beta-2 agonists can also reduce the amount of mucus in the lungs by speeding up the motion of cilia. Cilia are tiny hairs that line the walls of your airways and help 'sweep' mucus out of the airways.
Beta-2 agonists tend to be more effective in treating asthma than in treating chronic obstructive pulmonary disease (COPD).
Anticholinergics
Like beta-2 agonists, anticholinergics also relax the muscles in the lungs. Short-acting and long-acting varieties are available. Anticholinergics are mainly used to treat COPD.
Anticholinergics are usually taken through an inhaler, but people with severe COPD will need to use a nebuliser. This device uses air pressure to turn the medicine into a fine mist, which is then breathed in through a mask.
Theophylline
Theophylline is a long-acting bronchodilator that is usually used in the treatment of COPD. Exactly how theophylline works is unclear, but it seems to relax the muscles in the lungs, while reducing any possible inflammation (swelling) in the airways.
Theophylline is mostly taken in tablet or syrup form. Due to a risk of associated side effects (see bronchodilator drugs - side effects), theophylline is normally only used as a treatment if other bronchodilators are not effective.
