A case is described of urinary retention lasting 27 days after 15 days' treatment with amitriptyline hydrochloride (Tryptizol). The interesting features are 1) the long duration of the condition after the drug was stopped and 2) the failure of a cholinergic drug (carbachol) to counteract the anti-cholinergic activity of Tryptizol.The case demonstrates the necessity for daily examination for urinary retention of patients receiving amitriptyline HCL, particularly of cases who cannot be expected to make spontaneous complaint of urinary symptoms, due to dementia, depression or apathy.Abstract Teaser