Understanding Respiratory Relief: What are considered bronchodilators?

October 12, 2025 •

4 min read

Globally, an estimated 6.2% of the population has asthma and 4.9% has COPD, conditions often managed with medications that open the airways [1.8.1]. This article explores the question, 'What are considered bronchodilators?' and details their crucial role in managing these respiratory diseases.

Quick Summary

Bronchodilators are essential medications that relax airway muscles to make breathing easier for those with asthma or COPD. They come in short-acting and long-acting forms and work through different mechanisms.

Key Points

Definition: Bronchodilators are medications that relax muscles around the airways in the lungs, making it easier to breathe [1.2.1].
Primary Conditions: They are primarily used to treat asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and emphysema [1.3.3].
Main Classes: The three main types are beta-2 agonists, anticholinergics, and theophylline, each working differently to open airways [1.2.5].
Action Speed: They are classified as short-acting (rescue) for quick symptom relief and long-acting (maintenance) for daily symptom control [1.2.5].
Administration: The most common delivery methods are inhalers (MDI, DPI) and nebulizers, which direct medicine to the lungs [1.2.3, 1.7.3].
Not Steroids: Bronchodilators are not steroids; they relax airway muscles, while steroids reduce airway inflammation [1.10.2].
Combination Therapy: Long-acting bronchodilators are often used with inhaled corticosteroids for more comprehensive asthma and COPD management [1.2.5, 1.5.4].

The Role of Bronchodilators in Respiratory Health

Bronchodilators are a cornerstone of treatment for chronic lung diseases like asthma and Chronic Obstructive Pulmonary Disease (COPD) [1.3.1]. These medications work by relaxing the muscles that surround the airways (bronchi), causing them to widen, or dilate [1.2.1]. This action increases airflow to the lungs, providing relief from common symptoms like wheezing, shortness of breath, coughing, and chest tightness [1.3.1, 1.6.4]. In addition to relaxing airway muscles, they can also help clear mucus from the lungs, as the wider passages allow mucus to move more freely and be coughed out [1.2.5]. These medications are prescribed for various conditions, including asthma, COPD, emphysema, bronchitis, and sometimes severe allergic reactions [1.3.3].

How Do Bronchodilators Work? Mechanisms of Action

Bronchodilators function through different pharmacological pathways to achieve the same goal: opening the airways. The three main classes are beta-2 agonists, anticholinergics, and theophylline [1.2.5].

Beta-2 Agonists: This is the most common class of bronchodilators [1.3.4]. They work by stimulating beta-2 receptors located on the smooth muscle cells lining the airways [1.2.1]. This stimulation triggers a series of chemical reactions that cause the muscles to relax, leading to bronchodilation. They are known as functional antagonists because they reverse airway constriction regardless of the cause [1.5.3]. Examples include albuterol, salmeterol, and formoterol [1.2.2, 1.2.5].
Anticholinergics: These medications work by blocking the action of acetylcholine, a neurotransmitter that signals muscles to contract [1.2.1]. In the lungs, cholinergic nerves provide a baseline level of muscle tone. By blocking acetylcholine, anticholinergics prevent these muscles from tightening, thus keeping the airways open. They may also help reduce excess mucus production [1.3.2]. This class is particularly effective for treating COPD [1.4.1]. Examples include ipratropium and tiotropium [1.2.2, 1.2.5].
Theophylline: This older class of bronchodilator is now used less frequently due to a higher risk of side effects and the need for blood monitoring [1.6.2, 1.9.4]. Its exact mechanism is not fully understood, but it is believed to relax the airway muscles by inhibiting an enzyme called phosphodiesterase [1.9.4]. It is typically taken orally as a tablet or capsule for long-term control of severe asthma or COPD [1.2.5].

Types of Bronchodilators: Short-Acting vs. Long-Acting

Bronchodilators are categorized not only by their mechanism but also by their duration of action, which dictates their role in a treatment plan [1.2.1].

Short-Acting Bronchodilators (SABAs)

Often called "rescue" or "reliever" medications, short-acting bronchodilators provide rapid relief from acute symptoms [1.2.5, 1.11.1]. They begin working within minutes and their effects last for about four to six hours [1.2.1, 1.2.5]. They are used on an as-needed basis to stop sudden breathing problems.

Common Use: Treating acute asthma attacks, sudden COPD flare-ups, and preventing exercise-induced bronchospasm [1.2.5, 1.3.1].
Examples: Albuterol (a SABA) and Ipratropium (a short-acting muscarinic antagonist, or SAMA) [1.2.5, 1.4.3].

Long-Acting Bronchodilators (LABAs)

Known as "maintenance" or "controller" medications, long-acting bronchodilators are taken daily to manage chronic symptoms and prevent flare-ups [1.3.1, 1.11.1]. Their effects last for 12 hours or more, providing sustained control over airway constriction [1.2.1, 1.2.5]. They are not intended for quick relief of acute symptoms [1.11.1]. For asthma treatment, long-acting beta-agonists (LABAs) should be used in combination with an inhaled corticosteroid [1.2.5].

Common Use: Daily, long-term management of moderate to severe asthma and COPD [1.2.1, 1.3.1].
Examples: Salmeterol and Formoterol (LABAs), and Tiotropium (a long-acting muscarinic antagonist, or LAMA) [1.2.5, 1.4.3].

Administration and Side Effects

Bronchodilators are delivered in several forms, with inhaled methods being the most common because they deliver the medication directly to the lungs, minimizing systemic side effects [1.2.3, 1.9.4].

Metered-Dose Inhalers (MDIs): These are the familiar puff-style inhalers that deliver a pre-measured spray of medication [1.2.4].
Dry Powder Inhalers (DPIs): These devices deliver the medication as a fine powder that is inhaled with a deep, fast breath [1.2.4].
Nebulizers: A nebulizer is a machine that converts liquid medication into a fine mist, which is then inhaled through a mask or mouthpiece over 5 to 15 minutes [1.7.2, 1.7.3]. This is often used for young children or individuals who have difficulty using an inhaler [1.9.3].
Oral Forms: Some bronchodilators, like theophylline, are available as pills or liquids [1.2.5].

While generally safe and effective, bronchodilators can have side effects. These vary by class:

Beta-2 Agonists: May cause shakiness, nervousness, increased heart rate (palpitations), and muscle cramps [1.6.5].
Anticholinergics: Can lead to dry mouth, dry eyes, an unusual taste, and temporary blurred vision if the medication gets in the eyes [1.6.5].
Theophylline: Has a higher rate of side effects, including nausea, headaches, rapid heartbeat, and muscle cramps [1.6.5].


Feature	Beta-2 Agonists	Anticholinergics	Theophylline
Mechanism	Stimulate beta-2 receptors to relax airway muscles [1.2.1].	Block acetylcholine to prevent muscle contraction [1.2.1].	Inhibits phosphodiesterase to relax airway muscles [1.9.4].
Primary Use	Quick relief (SABA) and long-term control (LABA) for asthma and COPD [1.4.1].	Long-term control for COPD; also used for asthma [1.4.1, 1.3.5].	Long-term control for severe, persistent symptoms [1.2.5].
Onset	Fast (SABA), Slower (LABA) [1.2.4].	Slower than SABAs [1.2.5].	Slow (oral form) [1.2.3].
Examples	Albuterol (SABA), Salmeterol (LABA) [1.2.5].	Ipratropium (SAMA), Tiotropium (LAMA) [1.2.5, 1.4.3].	Theophylline [1.2.2].
Common Side Effects	Tremor, increased heart rate, nervousness [1.6.5].	Dry mouth, blurred vision, unusual taste [1.6.5].	Nausea, headache, rapid heartbeat [1.6.5].

Conclusion

Bronchodilators are a vital class of medications that provide significant relief for millions of people living with respiratory conditions like asthma and COPD. By understanding what bronchodilators are, their different types, and how they work, patients and caregivers can better manage treatment plans. They are available in both short-acting (rescue) and long-acting (maintenance) forms, allowing for both immediate symptom relief and long-term prevention of flare-ups. While not a cure, these therapies are essential for improving quality of life, increasing exercise tolerance, and allowing individuals with lung disease to breathe easier [1.3.3].

For more information, a valuable resource is the National Heart, Lung, and Blood Institute (NHLBI).

Frequently Asked Questions

No, a bronchodilator is not a steroid. Bronchodilators work by relaxing the muscles around the airways, while steroids (corticosteroids) work by reducing inflammation in the airways. The two are often used together but belong to different drug classes [1.10.2, 1.10.3].

A rescue inhaler contains a short-acting bronchodilator for fast relief of sudden symptoms like an asthma attack. A maintenance inhaler contains a long-acting medication (often a bronchodilator and/or a steroid) used daily to control chronic symptoms and prevent flare-ups [1.11.1, 1.11.4].

Common side effects, particularly for beta-2 agonists, include feeling shaky or nervous, a faster heartbeat (palpitations), and muscle cramps [1.6.5]. Anticholinergics may cause dry mouth [1.6.5].

Short-acting bronchodilators (rescue inhalers) work very quickly, usually within a few minutes, with effects lasting 4-6 hours. Long-acting bronchodilators have a slower onset and are designed to work over 12 to 24 hours [1.2.1, 1.2.5].

While you can use it when needed, relying on your rescue inhaler frequently is a sign that your respiratory condition may not be well-controlled. You should consult your healthcare provider, as you may need a daily maintenance medication [1.11.1].

Bronchodilators are primarily used to treat conditions that cause airway narrowing, such as asthma, chronic obstructive pulmonary disease (COPD), emphysema, and chronic bronchitis [1.3.1, 1.3.3].

A nebulizer is a machine that turns liquid bronchodilator medicine into a fine mist. This mist is inhaled through a mask or mouthpiece, which can be easier for young children or people who find it difficult to use an inhaler [1.7.1, 1.7.3].