Moderate
Amitriptyline × Propranolol
Tricyclic antidepressants (TCA)×Non-selective beta blocker
Mechanism
Additive bradycardia and orthostatic hypotension. Propranolol is non-selective (blocks β1 and β2); bradycardia risk is higher than with bisoprolol. Plus additive cardiac anticholinergic effect.
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope. In asthma or COPD: bronchospasm risk. Older patients: delirium and fall risk.
Management
In older patients, check pulse and blood pressure 1–2 weeks after starting amitriptyline. In asthma or COPD, a selective beta-blocker (bisoprolol, metoprolol) is preferable.