Which antidepressant is listed with strong anticholinergic properties and is noted with a dosing threshold of greater than 6 mg per day?

• A. Doxepin (>6 mg/day)
• B. Amitriptyline
• C. Imipramine
• D. Nortriptyline

Answer: (A)

In Beers Criteria practice, the concern is how strong anticholinergic effects can contribute to delirium, confusion, constipation, urinary retention, and other issues in older adults. Doxepin, a tricyclic antidepressant, has particularly strong anticholinergic activity once you exceed a daily dose of 6 mg. That dosing threshold is what the criteria highlight, flagging doxepin as problematic for older patients when used above this amount. While other TCAs like amitriptyline, imipramine, and nortriptyline also carry anticholinergic effects, the Beers entry specifically notes the strong anticholinergic property at a threshold above 6 mg per day for doxepin, which is why it’s identified in this way.