Moderate
Amitriptyline × Furosemide
Tricyclic antidepressants (TCA)×Loop diuretics
Mechanism
Additive orthostatic hypotension. Amitriptyline blocks α1-adrenoceptors and reduces the compensatory vascular response to hypovolaemia (from the diuretic).
Symptoms
Postural dizziness, syncope, fatigue. Older patients: fall and fracture risk.
Management
In older patients, check standing and sitting blood pressure 1–2 weeks after starting amitriptyline. Advise slow rising. For neuropathic pain, alternative: gabapentin or pregabalin (no α1-blockade).
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.