How does ProAir Respiclick (albuterol) work?

How ProAir RespiClick (Albuterol) Works

ProAir RespiClick works by stimulating beta-2 adrenergic receptors in bronchial smooth muscle, causing relaxation and bronchodilation, which improves airflow in patients with obstructive airway diseases like asthma. 1

Mechanism of Action

ProAir RespiClick contains albuterol, a short-acting beta-2 agonist (SABA) that:

• Stimulates adenyl cyclase, the enzyme that catalyzes formation of cyclic-3',5'-adenosine monophosphate (cyclic AMP) from adenosine triphosphate (ATP) 1
• The increased cyclic AMP mediates bronchial smooth muscle relaxation 1
• Preferentially affects beta-2 adrenergic receptors (which predominate in bronchial smooth muscle) compared to beta-1 receptors 1
• Provides rapid bronchodilation with minimal side effects 2

Pharmacokinetics

• Onset of action: Within 5 minutes after inhalation 2, 1
• Peak effect: 30-60 minutes 2
• Duration of action: 4-6 hours 2
• Absorption: Less than 20% of a single dose is absorbed following nebulizer administration 1
• Metabolism: Not a substrate for cellular uptake processes for catecholamines or catechol-O-methyl transferase, contributing to its longer duration of action compared to isoproterenol 1
• Elimination: Most of the absorbed dose is recovered in urine within 24 hours 1

Clinical Effects

ProAir RespiClick produces:

• Significant improvement in pulmonary function (FEV1) within 5 minutes 1
• Maximum average improvement in pulmonary function at approximately 1 hour 1
• Clinically significant improvement (defined as ≥15% increase in FEV1 over baseline) for 3-4 hours in most patients, and up to 6 hours in some 1

Delivery System Specifics

ProAir RespiClick is a breath-actuated multidose dry powder inhaler (MDPI) that:

• Does not use chlorofluorocarbon (CFC) propellants, which harm the ozone layer 3
• Instead uses hydrofluoroalkane (HFA) propellants, which have no ozone-depleting effects 3
• Delivers the same amount of drug per puff with similar particle size distribution as older CFC-based inhalers 3

Clinical Applications

ProAir RespiClick is indicated for:

1. Quick relief of acute asthma symptoms 4
2. Prevention of exercise-induced bronchospasm when used 15 minutes before exercise 4

Important Clinical Considerations

• ProAir RespiClick should be used less than daily on average for symptom relief 4
• Increasing use of albuterol (more than twice weekly) for symptom control generally indicates inadequate asthma control and the need for controller medication 2
• Regular use exceeding twice weekly for symptom control (not for prevention of exercise-induced bronchospasm) indicates the need for initiating or intensifying anti-inflammatory therapy 4, 2

Safety Profile

• Side effects are dose-related and more common with systemic (oral/IV) than inhaled administration 5
• Potential side effects include:
  • Cardiovascular: tachycardia, increased pulse pressure 5
  • Metabolic: decreased plasma potassium, increased glucose 5
  • Musculoskeletal: skeletal muscle tremor 5

Common Pitfalls to Avoid

1. Overreliance on rescue therapy: Using ProAir RespiClick more than twice weekly for symptom control suggests inadequate asthma management and need for controller medications 2

2. Improper inhaler technique: Proper technique is essential for effective medication delivery 2

3. Using for anaphylaxis management: While ProAir RespiClick may provide adjunctive therapy for wheezing during anaphylaxis, it does not replace epinephrine as the primary treatment 2

4. Oral vs. inhaled administration: Oral albuterol is less potent, has slower onset, and more side effects than inhaled formulations 2

ProAir RespiClick remains a cornerstone of rescue therapy for asthma, though recent evidence suggests that in some patients with inflammatory components, combining with inhaled corticosteroids may be more efficacious 6.