Role of Bricanyl (Terbutaline) in Acute COPD Exacerbations
Short-acting β2-agonists like terbutaline (Bricanyl) are recommended as initial bronchodilators for treating acute exacerbations of COPD, either alone for mild exacerbations or in combination with other treatments for moderate to severe cases. 1
Mechanism of Action and Pharmacology
- Terbutaline is a β2-adrenergic receptor agonist that relaxes bronchial smooth muscle by stimulating intracellular adenyl cyclase, increasing cAMP levels, which leads to bronchodilation 2
- After subcutaneous administration, terbutaline produces measurable changes in expiratory flow rate within 5 minutes, with clinically significant bronchodilation occurring within 15 minutes 2
- Maximum effect typically occurs within 30-60 minutes, with clinically significant bronchodilation lasting 1.5-4 hours 2
Treatment Recommendations for COPD Exacerbations
Initial Bronchodilator Therapy
- For moderate exacerbations, a β2-agonist (such as terbutaline 5-10 mg) or an anticholinergic drug (ipratropium bromide 0.25-0.5 mg) should be administered via nebulizer 1
- For severe exacerbations, or if response to either treatment alone is poor, both β2-agonists and anticholinergics may be administered together 1
- Nebulized bronchodilators should be given on arrival and at 4-6 hourly intervals thereafter, but may be used more frequently if required 1
Dosing and Administration
- Terbutaline can be administered at doses of 5-10 mg via nebulizer for acute exacerbations 1
- In patients with hypercapnic respiratory failure, the nebulizer should be driven by compressed air rather than oxygen, with supplemental oxygen provided via nasal prongs if needed 1
- Nebulized bronchodilators should be continued for 24-48 hours or until the patient shows clinical improvement 1
Evidence for Efficacy
- Short-acting β2-agonists improve post-bronchodilator lung function, decrease breathlessness, and reduce treatment failure in COPD patients 3
- However, a modeling study has questioned the effectiveness of nebulized terbutaline on clinically relevant parameters in decompensated COPD patients, finding limited influence on arterial blood gas parameters or heart rate 4
- In patients requiring non-invasive ventilation for COPD exacerbations, terbutaline alone was found to be as effective as the combination of terbutaline and ipratropium bromide in terms of hospital admission rates and need for ICU care 5
Potential Side Effects and Considerations
- β2-agonists may cause a fall in PaO2 due to pulmonary vascular effects, which does not occur with anticholinergic agents 1
- Common side effects include tachycardia, tremor, and hypokalemia 2, 4
- The intravenous route offers no advantage over nebulized administration in most acute exacerbations 1
Comprehensive Management Approach
- Classify COPD exacerbations as mild (treated with short-acting bronchodilators only), moderate (treated with short-acting bronchodilators plus antibiotics and/or oral corticosteroids), or severe (requiring hospitalization or emergency room visits) 1
- For mild exacerbations, short-acting β2-agonists alone may be sufficient 1
- For moderate to severe exacerbations, combine short-acting β2-agonists with:
Conclusion and Clinical Pearls
- Terbutaline is an effective first-line bronchodilator for acute COPD exacerbations, particularly for immediate symptom relief 1
- After the acute phase, transition to maintenance therapy with long-acting bronchodilators should be initiated as soon as possible before hospital discharge 1
- Methylxanthines (such as theophylline) are not recommended due to their side effect profile 1
- For severe exacerbations with suboptimal response to initial therapy, IV magnesium sulfate may be considered as an adjunctive treatment 6