Management of Metoprolol-Induced Respiratory Compromise

Immediate Recognition and Discontinuation

Stop metoprolol immediately when respiratory compromise develops, as active asthma or reactive airway disease represents an absolute contraindication to beta-blocker therapy, according to the American College of Cardiology 1, 2
Even at low doses, metoprolol can precipitate bronchospasm in susceptible patients, and cardioselectivity is dose-dependent and lost at higher doses, as noted by the American College of Cardiology 1, 3

Monitor respiratory status continuously with pulse oximetry and auscultation, as recommended by the American College of Cardiology 2

Assess for respiratory rate and work of breathing, looking for accessory muscle use, nasal flaring, or paradoxical breathing, as recommended by the American College of Cardiology 2
Maintain oxygen saturation above 92% with supplemental oxygen as needed, according to the American College of Cardiology 2
Listen for new or worsening bronchospasm in all lung fields, as recommended by the American College of Cardiology 2

Switch to a non-dihydropyridine calcium channel blocker such as diltiazem or verapamil, which do not cause bronchospasm, as recommended by the American Heart Association 4, 2
Consider ACE inhibitors, ARBs, or dihydropyridine calcium channel blockers, which have no effect on bronchial smooth muscle, according to the American College of Cardiology 1, 2

Do not attempt to "push through" mild respiratory symptoms by continuing metoprolol at lower doses, as even cardioselective beta-blockers lose selectivity and can worsen bronchospasm, as noted by the American College of Cardiology 1, 3
Do not assume all beta-blockers are equally safe, as metoprolol is relatively cardioselective but still blocks beta-2 receptors at therapeutic doses and is contraindicated in reactive airway disease, according to the American College of Cardiology 1, 3

Document the specific respiratory symptoms and their temporal relationship to metoprolol administration, as recommended by the American College of Cardiology 2
Note this as a drug allergy/contraindication in the patient's medical record to prevent future exposure, according to the American College of Cardiology 2
Consider pulmonary function testing if baseline respiratory status is unclear or if chronic lung disease is suspected, as recommended by the American College of Cardiology 1