How does albuterol (salbutamol) treat chronic obstructive pulmonary disease (COPD) exacerbation?

From the Guidelines

Albuterol is a crucial medication for treating COPD exacerbations, acting as a short-acting beta-2 agonist (SABA) that rapidly relaxes bronchial smooth muscle, providing quick relief of bronchospasm and airflow obstruction. According to the most recent and highest quality study 1, short-acting inhaled β2-agonists, with or without short-acting anticholinergics, are recommended as the initial bronchodilators to treat an acute exacerbation. During a COPD exacerbation, albuterol is typically administered via a metered-dose inhaler (MDI) with a spacer or through a nebulizer. The standard dosing is 2-4 puffs (90 mcg per puff) every 4-6 hours as needed via MDI, or 2.5 mg via nebulizer every 4-6 hours. For severe exacerbations, it may be given more frequently, such as every 20 minutes for the first hour, then hourly as needed.

Albuterol works by binding to beta-2 receptors in the lungs, activating adenylyl cyclase which increases intracellular cyclic AMP. This leads to relaxation of bronchial smooth muscle, decreased release of inflammatory mediators, and improved mucociliary clearance. Patients should be monitored for potential side effects including tachycardia, tremors, and hypokalemia, especially when higher doses are used. Albuterol is often combined with anticholinergics like ipratropium bromide and systemic corticosteroids for optimal management of COPD exacerbations, as supported by 1.

Key points to consider in the management of COPD exacerbations include:

• The goal of treatment is to minimize the negative impact of the current exacerbation and to prevent subsequent events 1
• Systemic corticosteroids improve lung function and oxygenation, and shorten recovery time and hospitalization duration 1
• Antibiotics, when indicated, can shorten recovery time and reduce the risk of early relapse, treatment failure, and hospitalization duration 1
• Noninvasive ventilation (NIV) should be the first mode of ventilation used in patients with COPD with acute respiratory failure who have no absolute contraindication 1

Overall, albuterol is a vital component of COPD exacerbation management, and its use should be guided by the most recent and highest quality evidence.

From the FDA Drug Label

The prime action of beta-adrenergic drugs is to stimulate adenyl cyclase, the enzyme which catalyzes the formation of cyclic-3',5'-adenosine monophosphate (cyclic AMP) from adenosine triphosphate (ATP). Albuterol has been shown in most controlled clinical trials to have more effect on the respiratory tract in the form of bronchial smooth muscle relaxation than isoproterenol at comparable doses while producing fewer cardiovascular effects In controlled clinical trials, most patients exhibited an onset of improvement in pulmonary function within 5 minutes as determined by FEV1. Clinically significant improvement in pulmonary function (defined as maintenance of a 15% or more increase in FEV1 over baseline values) continued for 3 to 4 hours in most patients and in some patients continued up to 6 hours

Albuterol treats chronic obstructive pulmonary disease (COPD) exacerbation by stimulating beta2-adrenergic receptors, causing bronchial smooth muscle relaxation. This leads to an improvement in pulmonary function, as measured by FEV1, within 5 minutes of administration, with clinically significant improvement lasting for 3 to 4 hours in most patients and up to 6 hours in some patients 2.

From the Research

Treatment of COPD Exacerbation with Albuterol

• Albuterol is a short-acting bronchodilator used to treat chronic obstructive pulmonary disease (COPD) exacerbations 3, 4.
• The first step in outpatient management of COPD exacerbations is to increase the dosage of inhaled short-acting bronchodilators, such as albuterol 3.
• Combining ipratropium and albuterol is beneficial in relieving dyspnea in patients with COPD exacerbations 3, 5.

Mechanism of Action

• Albuterol works by relaxing the muscles in the airways, making it easier to breathe 4.
• The combination of ipratropium and albuterol has been shown to be more effective than either agent alone in improving lung function in patients with COPD 5, 6.

Clinical Evidence

• Randomized controlled trials have demonstrated the effectiveness of multiple interventions, including albuterol, in treating COPD exacerbations 3.
• A 12-week prospective, double-blind, parallel-group evaluation of albuterol, ipratropium, and a combination of the two found that the combination was superior to either single agent alone in peak effect and total area under the curve of the FEV1 response 5.
• A review of the evidence in the prehospital treatment of adult patients with respiratory distress found that albuterol improved symptoms and peak flow rates in patients with bronchospastic disease 7.

Combination Therapy

• The combination of ipratropium and albuterol has been shown to reduce daily variability in FEV1 compared to monotherapy 6.
• The free combination of albuterol and ipratropium resulted in greater improvements and lower day-to-day variability in FEV1 compared to either monotherapy or no bronchodilator therapy 6.