Moderate
Amitriptyline × carvedilol
Tricyclic antidepressants (TCA)×Alpha and beta blocker (non-selective β + α1)
Mechanism
TCA blocks α1-adrenoceptors — additive orthostatic hypotension with carvedilol (α/β-blocker). Amitriptyline's additive bradycardia and QT effect intensify as heart rate drops with carvedilol.
Symptoms
Postural dizziness, syncope, fatigue. Older patients: fall and fracture risk.
Management
On starting the combination, begin amitriptyline at 10 mg at bedtime. In older patients, do not exceed 25 mg/day. Check standing/sitting BP, heart rate, and ECG at 2 weeks. For neuropathic pain, alternatives: gabapentin or pregabalin. For depression: sertraline or escitalopram (minimal cardiovascular effect).
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.