In respiratory diseases like asthma and chronic obstructive pulmonary disease, or COPD, airways constrict and cause difficulty breathing. When the muscles around the airways constrict, it is called a bronchospasm, and makes breathing difficult. Medications called bronchodilators help relax the muscles around the airways, keeping the bronchi open and allowing easier breathing.
Long-Acting Beta Agonists
Long-acting beta agonists are drugs that open up, or dilate, the airways by relaxing the muscles that surround them, making breathing easier, according to the Palo Alto Medical Foundation. For asthma, they are only effective when taken with an inhaled corticosteroid; these are taken every day, even when there are no symptoms. This kind of bronchodilator does not immediately relieve symptoms, but is rather used to prevent symptoms, especially in exercise-induced asthma. The Palo Alto Medical Foundation lists the medication serevent, brand name Salmeterol, as a long-acting beta agonist. Typical side effects of these medications include headache, upper respiratory infection and cough.
Short-Acting Bronchodilators
The National Jewish Health website describes short-acting bronchodilators as drugs that work quickly, usually within 20 minutes, to relieve symptoms. Other names for these drugs include rescue medications and short-acting beta agonists. They come in metered-dose inhalers or in solutions for nebulizers, says the Palo Alto Medical Foundation, and although an oral solution is available, it is rarely given because it is not as effective. Drugs that fall into this category include Albuterol, Proventil and Ventolin.
Anticholinergic Bronchodilators
The American Association for Respiratory Care, or AARC, describes another type of bronchodilator, the anticholinergic bronchodilators. These drugs work on the chemical acetylcholine, which the body produces when in contact with irritants. Acetylcholine causes airway constriction, according to the AARC, and these drugs block acetylcholine, keeping the airways open. These medications also work with the parasympathetic nervous system, which the AARC says controls the airway size. Metered-dose inhalers are used to administer these drugs, which last four to six hours. These drugs are the number one bronchodilator of choice for treating COPD, according to the AARC. Drugs in this category include Atrovent and Combivent, which combines an anticholinergic with albuterol. Side effects are few, but may include nervousness and cough.
Theophylline
The AARC defines theophylline as an oral bronchodilator. This medication dilates the airways, increases muscle endurance and reduces muscle fatigue. This is taken daily, once or twice a day, but as of 2010 is prescribed less frequently because of side effects, which can include nausea, vomiting, insomnia and headaches.
