BPH Medications, Bethanechol, and Urinary Retention

Benign prostatic hyperplasia is hyperplastic growth of stromal and epithelial cells in the prostate’s transition zone. As that tissue enlarges, it narrows the bladder outlet and increases resistance to urine flow. The bladder may compensate by generating stronger contractions, but persistent obstruction eventually contributes to incomplete emptying and urinary retention. BPH commonly produces gradually progressive lower urinary tract symptoms: hesitancy, a weak or intermittent stream, straining, post-void dribbling, urgency, frequency, and nocturia. These symptoms do not prove that BPH is the cause. Infection, medication effects, neurologic disease, urethral narrowing, bladder dysfunction, and malignancy can produce a similar pattern. Urinary retention is a functional problem, not merely “more severe frequency.” Acute retention presents as an abrupt inability to void, often with suprapubic pain, fullness, or visible distress. Chronic retention may produce little pain despite a substantial residual volume. A patient who reports “I have not urinated all day” needs assessment of bladder distention and perfusion rather than reassurance based on the absence of discomfort. The central distinction is whether the detrusor cannot contract effectively or whether urine cannot pass through the...