What are bronchodilators?
Bronchodilators are a type of medicine used to prevent and treat symptoms of chronic obstructive pulmonary disease (COPD), such as wheezing, breathlessness, and chest tightness.
Bronchodilator medications are a key part of managing COPD symptoms. Many people with COPD use at least one kind of bronchodilator as part of their treatment regimens.1 It is also common for patients to have more than one type of bronchodilator to manage different parts of the disease.2 This is because different bronchodilators can work in different ways to relieve symptoms.
How do bronchodilators work?
People with COPD have airways that are irritated and swollen. This can cause the band of muscles that surround the airways to tighten up all of a sudden, which is called a “bronchospasm.” When this happens, the airways get narrower and it makes it difficult to breathe.
Bronchodilators treat bronchospasms by affecting the muscles around the airways. They can make the muscles relax when they are too tight, and keep them from tightening up again. When the muscles are relaxed, the airways become wider, which allows more air to travel in and out of the lungs.1 This can make breathing easier for people with COPD.
Patients usually take bronchodilators using an inhaler or a nebulizer.
- Metered-dose inhalers (“MDIs” for short) deliver the medicine as a mist or spray that comes out of a canister and is inhaled by mouth.
- Dry-powdered inhalers (“DPIs” for short) deliver a dry powder through the inhaler, instead of a mist or spray.
- Nebulizers are special machines that change medicine from liquid form into a very fine mist that can be more easily absorbed in the lungs when inhaled.
Some kinds of bronchodilators are used as “rescue” or “reliever” inhalers. This means that are used as needed to very quickly relieve bronchospasms and breathing symptoms that suddenly get worse. This can sometimes help to keep flare-ups from becoming more severe.
During the early stages of COPD, a rescue inhaler may be the only medicine a patient needs to manage breathing symptoms.3
Other kinds of bronchodilators are used as “maintenance” medicines. This means that they are taken on a long-term, regular basis to help prevent and reduce the “everyday” symptoms of COPD.2 These are not used to treat bronchospasms or sudden symptoms. COPD patients in later stages of the disease use maintenance medicines more often.
What kinds of bronchodilators are there?
Bronchodilator medications commonly used to treat COPD include:
- Beta-agonist bronchodilators1
- Anticholinergic or antimuscarinic bronchodilators1,2
However, the use of methylxanthines in treating people with COPD is controversial, and they are generally only used in select cases when people have not responded to short-acting bronchodilators.3 Methylxanthines have significant side effects, and their benefits are inconsistent.
Bronchodilators are available in short-acting and long-acting forms:
- Short-acting beta-agonist bronchodilators – called “SABAs” for short
- Short-acting antimuscarinic bronchodilators – called “SAMAs” for short
- Long-acting beta-agonist bronchodilators – called “LABAs” for short
- Long-acting muscarinic agonists bronchodilators – called “LAMAs” for short
How are short-acting bronchodilators used to treat COPD?
Short-acting bronchodilators start working to relieve COPD symptoms quickly, but their effects do not last very long. SABAs are the most common type of rescue inhaler. SABAs can start providing relief for symptoms in 3 to 5 minutes, but are only effective for about 4 to 6 hours.1
SAMAs start working a little more slowly than SABAs do. They take about 15 minutes to start working, so they cannot be used as a rescue inhaler but are used as a maintenance therapy for COPD.2
How are long-acting bronchodilators used to treat COPD?
Long-acting bronchodilators are often used as maintenance therapy for COPD patients in later stages.3 These patients may have trouble breathing most of the time, or all of the time. Patients need to take long-acting bronchodilators every day in order for them to work well. Having a regular amount of the drug in the patient’s body all the time helps to provide more constant relief for COPD symptoms.
Long-acting bronchodilators include LABAs, LAMAs, phosphodiesterase-4 (PDE4) inhibitors and methylxanthines.4