Respiratory Insufficiency in Propranolol Overdose

Pathophysiology

• The American College of Cardiology notes that propranolol-induced respiratory insufficiency is primarily caused by cardiovascular collapse and central nervous system depression, rather than bronchospasm, although bronchospasm can occur as a secondary complication in patients with pre-existing reactive pulmonary disease 2
• The mechanism of respiratory insufficiency in propranolol overdose involves multiple cardiovascular and neurological mechanisms, including direct myocardial depression due to beta-blockade, which impairs sympathetic stimulation vital for maintaining circulatory function, leading to hypoperfusion and secondary respiratory failure 1

Clinical Manifestations

• The American College of Cardiology recommends that the initial approach should focus on cardiovascular stabilization and ventilatory support, rather than primary treatment of bronchospasm, as bronchospasm is a rare cause of respiratory insufficiency in propranolol overdose 2
• Propranolol is contraindicated in patients with reactive pulmonary disease (asthma, COPD) because it can provoke bronchospasm by blocking beta-2 receptor-mediated bronchodilation, occurring in 3-13% of patients on therapeutic use, mainly in those with pre-existing pulmonary disease 1, 2