Inhaled Anticholinergics for COPD and Asthma Management
The main inhaled anticholinergics used in respiratory medicine are tiotropium, aclidinium, ipratropium, and oxitropium, which are effective bronchodilators for the management of COPD and, to a lesser extent, asthma. 1
Types of Inhaled Anticholinergics
Short-Acting Anticholinergics
Ipratropium bromide
- Duration: 4-6 hours 1
- Requires administration every 6 hours
- Available in metered-dose inhalers and nebulizer solutions
Oxitropium bromide
- Duration: 6-8 hours 1
- Less commonly used in the US
Long-Acting Anticholinergics
Tiotropium bromide
Aclidinium bromide
- Duration: 12 hours
- Twice-daily dosing
- FDA-approved for maintenance treatment of COPD 5
- Available as dry powder inhaler (Pressair/Genuair)
Mechanism of Action
Anticholinergic agents work by:
- Blocking muscarinic receptors in airway smooth muscle 6
- Inhibiting acetylcholine-induced bronchoconstriction
- Reducing vagal tone, which appears to be the dominant reversible component in COPD 1, 7
Clinical Applications
In COPD
- Anticholinergics are considered first-line bronchodilators for COPD 1
- Long-acting anticholinergics (e.g., tiotropium) are recommended as monotherapy for symptomatic patients with FEV₁ <60% predicted 1
- More effective in COPD than in asthma 1
- Can be used in combination with long-acting β-agonists for additional benefit 1
In Asthma
- Tiotropium has shown benefit as add-on therapy in moderate to severe asthma uncontrolled on combination therapy with inhaled corticosteroids and long-acting β-agonists 4
- Particularly useful in patients with the asthma-COPD overlap syndrome 1
Advantages and Side Effects
Advantages
- Few systemic side effects due to poor absorption when inhaled 8
- No development of tolerance with chronic therapy 1
- No significant effects on mucociliary clearance 1
Common Side Effects
- Dry mouth (most common)
- Unpleasant taste
- Cough after inhalation 1
Potential Concerns
- Worsening of narrow-angle glaucoma (use with caution) 5
- Worsening of urinary retention, especially in patients with prostatic hyperplasia 5
- Potential for paradoxical bronchospasm (rare) 5
Important Clinical Considerations
- Anticholinergics should not be used for acute relief of symptoms (not rescue medications) 5
- Avoid using multiple anticholinergic medications simultaneously due to additive effects 5
- Proper inhaler technique should be taught at first prescription and checked periodically 1
- During acute exacerbations, some breathless patients may find nebulized delivery easier to use 1
Anticholinergic bronchodilators represent a cornerstone therapy for COPD management and have an expanding role in asthma treatment, particularly for patients who remain symptomatic despite standard therapies.