Bronchodilators relieve asthma symptoms by relaxing the muscle bands that tighten around the airways. This action rapidly opens the airways, letting more air come in and out of the lungs. As a result, breathing improves. Bronchodilators also help clear mucus from the lungs. As the airways open, the mucus moves more freely and can be coughed out more easily.
In short-acting forms, bronchodilators relieve or stop asthma symptoms and are very helpful during an asthma attack. In long-acting forms, bronchodilators help control asthma symptoms and prevent asthma attacks.
Two main types of bronchodilator medicines
(Beta 2-agonists [long & short acting] and Anticholinergic drugs)
Beta 2-agonists - Short-acting inhaled forms include:
- Albuterol (Proventil® HFA, Ventolin® HFA, Accuneb®, ProAir®)
- Metaproterenol (Alupent®)
- Levalbuterol (Xoponex® HFA, Xoponex® nebulizer solution)
- Pirbuterol (Maxair®)
- Albuterol and ipatropium bromide combination (Combivent® metered dose inhaler; DuoNeb®)
Short-acting beta 2-agonists are also called "quick acting" or "rescue" medicines because they relieve asthma symptoms very quickly by opening the airways. These inhalers are the best for treating sudden and severe or new asthma symptoms. They work within 20 minutes and last four to six hours. They are also the medicines to use 15 to 20 minutes before exercise to prevent exercise-induced asthma symptoms. Albuterol is also available in oral form as pills or liquid. Overuse of short-acting beta 2-agonists is a sign of unstable asthma. If you need to use your short-acting beta 2-agonists more than twice per week, talk to your doctor about increasing the amounts of long-term control medicines you take, such as inhaled steroids and long-acting beta 2-agonists (see below).
Beta 2-agonists - Long-acting forms include:
- Salmeterol (Serevent®)
- Formoterol (Foradil®)
- Combination medications: salmeterol and fluticasone (Advair®); formoterol and budesonide (Symbicort®). These contain both the long acting beta agonist and an inhaled corticosteroid. Symbicort® has recently been approved by the FDA.
Note: The long-acting forms of beta 2-agonists are use to provide control — NOT QUICK RELIEF — of asthma. These drugs may take longer to begin to work, but their benefits last 12 hours.
Salmeterol and formoterol are the only inhaled, long-acting beta 2-agonists available. They are used twice a day to maintain open airways for long term-control and should be used in conjunction with an inhaled corticosteroid for the treatment of asthma. They have also been shown to be helpful in treating exercise-induced asthma. They are available in dry powder inhaler (DPI) form.
Side effects of beta 2-agonists include:
- Nervous or shaky feeling
- Overexcitement or hyperactivity
- Increased heart rate
- Upset stomach (rare)
- Trouble sleeping (rare)
Oral forms of beta 2-agonists (pills or syrups) tend to have more side effects because they are in higher doses and are absorbed throughout the bloodstream to get to the lungs. Inhaled forms are deposited directly in the lungs and therefore have fewer side effects.
Anticholinergic drugs
There are two anticholinergic bronchodilators currently available—Ipratropium bromide (Atrovent® HFA), which is available as a metered dose inhaler and nebulizer solution, and tiotropium bromide (Spiriva®), which is a dry powder inhaler. Ipratropium is used 4 times per day whereas tiotropium is used only once per day as its action lasts for 24 hours. These are not quick relief medications but medications that can enhance the bronchodilator effect for certain asthmatics with difficult-to-control symptoms. Although not commonly used to treat asthma, they can be of benefit to some patients.
Side effects are minor; dry throat is the most common. If the medicine gets in your eyes, it might cause blurred vision for a short period of time.
Theophylline
Theophylline is another type of bronchodilator that is used to control asthma. Brand names include Uniphyl®, Theo-Dur®, Slo-Bid®, and Theo-24®. Theophylline is available as a pill or as an intravenous (through the vein) drug. It is long-acting and prevents asthma attacks. Theophylline is used to treat difficult-to-control or severe asthma and must be taken daily.
Side effects include:
- Nausea and/or vomiting
- Diarrhea
- Stomach ache
- Headache
- Rapid or irregular heartbeat
- Muscle cramps
- Jittery or nervous feeling
- Hyperactivity
These side effects might be a warning of too much medicine. Your doctor will check your blood levels to make sure you’re receiving the proper amount.
Always tell your doctors if you take theophylline for asthma because certain medicines —such as antibiotics containing erythromycin or seizure and ulcer medicine—can interfere with the way theophylline works. Also, viral illnesses and cigarette smoking can change how your body responds to theophylline.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 3/9/2007
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