Moderate
Amitriptyline × celecoxib
Tricyclic antidepressants (TCA)×Selective COX-2 inhibitor (coxib)
Mechanism
Additive anticholinergic effect (amitriptyline pronounced, celecoxib mild). In older patients, side-effect severity intensifies.
Symptoms
Dry mouth, constipation, urinary retention, accommodation disturbance, tachycardia. In older patients: delirium and confusion risk.
Management
On the combination, reassess the celecoxib benefit — for osteoarthritis, alternatives: topical NSAIDs or paracetamol up to 2 g/day. Avoid the combination in older patients. If unavoidable, cap amitriptyline at 25 mg/day. For constipation: fibre and adequate fluid intake (1.5 L/day).
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.