A bronchodilator is a medication that relaxes and opens the airways, or bronchi, in the lungs.
Short-acting and long-acting bronchodilators treat various lung conditions and are available by prescription.
Respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), cause bronchospasm, which is constriction or narrowing of the airways. Narrowed airways make it hard for a person to cough mucus up. It also makes it difficult for them to get air in and out of the lungs.
Taking a bronchodilator helps dilate or widen the airways, which makes it easier to breathe.
In this article, we look at how bronchodilators work, the various types, and how to take them.
Bronchodilators work by relaxing the muscles in the airways. The relaxation causes the airways to open up and the bronchial tubes to widen. Various types work in slightly different ways.
Classifications of bronchodilators include beta 2-agonists, anticholinergics, and xanthine derivatives. These medications open the airways, but they work on different receptors in the body.
Beta 2-agonists stimulate beta-adrenoceptors in the airway. This class of bronchodilator causes the smooth muscles surrounding the airways to relax. This improves airflow and reduces symptoms, such as shortness of breath.
Anticholinergic bronchodilators block the action of acetylcholine. Acetylcholine is a chemical released by the nerves that can lead to tightening of the bronchial tubes. By blocking the chemical, anticholinergic bronchodilators cause the airways to relax and open.
Xanthine derivatives also relax the airway muscles, although doctors do not know precisely how they work. The main xanthine derivative is theophylline.
Doctors rarely prescribe theophylline anymore because many people experience significant side effects. However, theophylline is available in capsule, tablet, or liquid form.
There are two main types of bronchodilators: long-acting and short-acting. Both types have a role in treating common lung diseases, such as asthma and emphysema.
Both beta 2-agonists and anticholinergic bronchodilators come in a short-acting and long-acting form.
Doctors often call short-acting bronchodilators rescue or fast-acting inhalers because they treat symptoms that come on suddenly, such as wheezing, shortness of breath, and chest tightness.
Short-acting bronchodilators work quickly, usually within a few minutes. Although they work fast, the therapeutic effects generally only last 4–5 hours. Short-acting bronchodilators treat sudden symptoms, and people do not need to use them when they are symptom-free.
Common short-acting bronchodilators include:
- albuterol (ProAir HFA, Ventolin HFA, Proventil HFA)
- levalbuterol (Xopenex HFA)
- pirbuterol (Maxair)
According to the American Academy of Allergy, Asthma, and Immunology, if a person needs fast-acting bronchodilators daily, they are not controlling their symptoms well and may need a long-acting bronchodilator.
Long-acting bronchodilators do not work as quickly as short-acting bronchodilators and do not treat acute or sudden symptoms.
The effects typically last for 12–24 hours, and people take them daily to prevent symptoms from developing.
Common long-acting bronchodilators include:
- salmeterol (Serevent)
- formoterol (Perforomist)
- aclidinium (Tudorza)
- tiotropium (Spiriva)
- umeclidinium (Incruse)
People usually use inhaled versions of bronchodilators because inhaling the medication allows it to get to the lungs fast. It also allows a person to take smaller doses of the drug and results in fewer body-wide side effects than when people take them orally.
The best type of bronchodilator to take may depend on a person's age, their level of consciousness, and their preference. Matching the best device to the person's ability will provide the most effective treatment.
It is important to understand how to take bronchodilators correctly to ensure that the most medication possible gets to the lungs. The most common ways of administering bronchodilators include:
Metered dose inhalers
A metered dose inhaler (MDI) is a small, pressurized canister that contains medication. The device releases the medicine when a person presses down on the canister. A propellant in the MDI carries the dose of medicine into the lungs.
A nebulizer uses bronchodilator medication in the form of a liquid and turns it into an aerosol that the person then inhales through a mouthpiece.
Dry powder inhaler
A dry powder inhaler does not have a propellant, and the bronchodilator is in powder form.
Soft mist inhaler
Some bronchodilators are available in soft mist inhalers. Soft mist inhalers deliver an aerosol cloud into the lungs without a propellant.
Research published in the International Journal of Chronic Obstructive Pulmonary Disease indicates that aerosol from a soft mist inhaler are slower-moving and longer-lasting than those from MDIs, meaning they deliver more medication to the lungs and less on the back of the throat.
Additional forms of bronchodilators include tablets and syrups.
Determining the best way to administer a bronchodilator is vital to ensure that a person gets the correct dose of medication. For example, if a person cannot effectively coordinate taking an MDI, some of the medication may end up in the back of the throat or the mouth instead of the lungs.
Similar to most types of medications, bronchodilators may have side effects.
The severity of the side effects is sometimes dose-dependent. The higher the dose, the more likely it is that side effects may develop. However, side effects can also occur with small doses.
Side effects may also differ depending on whether the bronchodilator is a beta 2-agonist or an anticholinergic. Possible side effects of bronchodilators include:
It is also possible that a bronchodilator can have the opposite effect and make constriction worse or lead to bronchospasm. As with all medications, an allergic reaction is also possible with bronchodilators.
Bronchodilators are a class of medication that relax the muscles surrounding the airways. Bronchodilators are one of the main treatments for respiratory diseases, such as asthma, emphysema, and chronic bronchitis.
The two types of bronchodilators prescribed for lung disease include short-acting and long-acting medications. Although bronchodilators can reduce symptoms, such as wheezing and trouble breathing, they may also cause side effects.
People with lung conditions can work with their healthcare provider to determine if the benefits of bronchodilators outweigh the possible side effects.