Moderate
Metoprolol × Theophylline
Selective β1-adrenoceptor blockers×Methylxanthine
Mechanism
Metoprolol is cardioselective but at high doses antagonises theophylline's bronchodilator effect. In bronchial asthma, control may worsen.
Symptoms
Exertional dyspnoea, wheezing, more frequent asthma attacks. In COPD: symptom exacerbation.
Management
In asthma and COPD with atrial fibrillation or hypertension, metoprolol is preferred at cardioselective doses (up to 100 mg/day) under pulmonary function monitoring. In severe asthma, consider alternatives — diltiazem or verapamil for rate control in atrial fibrillation. Theophylline is second-line in COPD; consider switching to long-acting beta-2 agonists (formoterol).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.