Urinary retention caused by mirtazapine in a patient with geriatric depression: A case report.

Depression, dementia, and delirium comprise the "3 Ds" of mental illness diagnoses in the older population. Depression is a common condition. Older adults may passively deal with depression, may not adhere to their prescribed drug schedules, and may be prone to unexpected side effects. A 70-year-old man with depression was brought by his family to the clinic with a 2-month history of depressed mood and poor drug compliance. After being diagnosed with depression, mirtazapine treatment was started. The following day, his family members suspected that the use of psychiatric drugs had caused acute urinary retention; hence, they brought him back to the emergency department. The emergency physician diagnosed the patient with benign prostatic hyperplasia and admitted him to the psychiatric ward after urinary catheterization. This case illustrates the effects of mirtazapine on urinary function in older individuals, particularly those with a history of benign prostatic hyperplasia. Although low-dose short-acting benzodiazepines and non-benzodiazepine hypnotics (Z-drugs) have been used to reduce the anticholinergic cognitive burden, mirtazapine inevitably induces acute urinary retention in older males with benign prostatic hyperplasia. Thus, the possibility of acute urinary retention caused by mirtazapine, particularly in patients with benign prostatic hyperplasia, cannot be ignored.