Do Opioids Cause Bronchospasm?
Opioids rarely cause clinically significant bronchospasm in patients with asthma or COPD, and when bronchospasm does occur, it is primarily mediated by histamine release from certain opioid drugs rather than a direct pharmacologic effect on bronchial smooth muscle. 1, 2
Mechanism and Clinical Reality
Histamine-mediated bronchospasm is uncommon and drug-specific. Certain opioids (particularly morphine, codeine, and meperidine) can trigger mast cell degranulation and histamine release, but this rarely provokes bronchospasm even in susceptible patients 1
The British Thoracic Society guidelines acknowledge a theoretical risk of bronchospasm with nebulized opioids and recommend pretreatment with β-agonists before administering nebulized morphine, diamorphine, or fentanyl for palliation of breathlessness 3
Histamine released by opioids in normal therapeutic doses does not lead to anaphylactoid reactions or clinically significant bronchospasm in normal patients 1
Primary Respiratory Concern: Depression, Not Bronchospasm
The dominant respiratory risk from opioids is ventilatory impairment (respiratory depression), not bronchospasm 3, 1
Opioid-induced ventilatory impairment occurs through three mechanisms: depression of the brainstem respiratory center, reduced upper airway muscle tone causing obstruction, and increased sedation with reduced arousal 3
Respiratory depression is the mechanism that causes morbidity and mortality in COPD patients receiving opioids, not bronchospasm 4, 5, 6
Evidence from COPD and Asthma Populations
Among 169,517 older adults with COPD receiving new opioid prescriptions, 2.9% experienced adverse pulmonary events within 30 days, but these events were respiratory depression-related (COPD exacerbations, pneumonia, respiratory failure), not bronchospasm 5
Concurrent use of opioids with benzodiazepines in COPD patients increases the risk of respiratory hospitalization (adjusted OR 2.32), again through ventilatory impairment rather than bronchospasm 4
The British Thoracic Society notes that bronchodilators are not contraindicated in any patient group with cystic fibrosis, implying that opioid-induced bronchospasm is not a recognized clinical barrier 3
Practical Clinical Approach
When prescribing opioids to patients with reactive airway disease:
Do not routinely withhold opioids due to bronchospasm concerns in patients with asthma or COPD—the risk is negligible compared to the risk of respiratory depression 1, 2
If using nebulized opioids for palliative breathlessness, pretreat with β-agonist bronchodilators as a precautionary measure 3
Avoid morphine and codeine in patients with severe respiratory compromise not because of bronchospasm risk, but because their active metabolites accumulate and worsen respiratory depression 7
Consider buprenorphine as the safest opioid option in patients with COPD or respiratory compromise due to its ceiling effect on respiratory depression 7
Monitor for respiratory depression (reduced respiratory rate, oxygen desaturation, hypercapnia), not bronchospasm, as the primary safety concern 3
Common Pitfall to Avoid
Do not confuse opioid-induced respiratory depression with bronchospasm. Patients experiencing opioid toxicity present with reduced respiratory rate, sedation, and hypercapnia—not wheezing, chest tightness, or prolonged expiration typical of bronchospasm 3, 1
The theoretical concern about histamine-mediated bronchospasm has never been demonstrated to cause clinically significant harm in appropriately monitored patients 7, 1