ModerateTricyclic antidepressants (TCA)×Second-generation antihistamines
Updated · Methodology
Mechanism
Additive anticholinergic effect and sedation. Cetirizine is a second-generation antihistamine with minimal central activity, but the effect adds up with amitriptyline. Older patients: high delirium risk.
Symptoms
Dry mouth, constipation, urinary retention (anticholinergic effect). Drowsiness, ataxia. Older patients: delirium and fall risk.
Management
In older patients, an alternative antihistamine with minimal anticholinergic load: fexofenadine or bilastine. Take cetirizine during the day, not at bedtime. Monitor cognition in prolonged therapy.
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.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Amitriptyline HCl tablets prescribing information (2014)– ; DailyMed setid 4e520c63-1cf6-40f6-a51c-3f9b0e181342