Name two main drug classes used to treat BPH and describe their mechanism.

Name two main drug classes used to treat BPH and describe their mechanism.

• A. Antibiotics and diuretics.
• B. Calcineurin inhibitors and mTOR inhibitors.
• C. Anticholinergics and PDE5 inhibitors.
• D. Alpha-blockers relax smooth muscle in the prostate and bladder neck; 5-alpha-reductase inhibitors decrease androgen-driven prostate growth.

Answer: (D)

Treating BPH mainly aims to reduce obstruction by addressing two components: smooth muscle tone (dynamic) and prostate size (static). Alpha-blockers work by blocking alpha-1 receptors on prostatic smooth muscle and the bladder neck. This causes immediate relaxation of these muscles, lowers resistance to urine flow, and quickly improves symptoms such as weak stream and incomplete emptying. They’re fast-acting and often used for rapid relief, with examples like tamsulosin and other uroselective agents. 5-alpha-reductase inhibitors reduce the conversion of testosterone to dihydrotestosterone, the hormone that drives prostate growth. By lowering DHT, these drugs slow or reverse prostate enlargement over months, reducing the static component of obstruction and lowering the risk of progression in men with larger prostates. Examples include finasteride and dutasteride. Other drug classes aren’t considered first-line mainstays for BPH because they don’t target these two primary mechanisms: antibiotics treat infection; calcineurin or mTOR inhibitors are immunosuppressants; anticholinergics and PDE5 inhibitors may help with certain symptoms but don’t address both dynamic and static components as effectively as the combination of an alpha-blocker and a 5-alpha-reductase inhibitor.

Treating BPH mainly aims to reduce obstruction by addressing two components: smooth muscle tone (dynamic) and prostate size (static).

Alpha-blockers work by blocking alpha-1 receptors on prostatic smooth muscle and the bladder neck. This causes immediate relaxation of these muscles, lowers resistance to urine flow, and quickly improves symptoms such as weak stream and incomplete emptying. They’re fast-acting and often used for rapid relief, with examples like tamsulosin and other uroselective agents.

5-alpha-reductase inhibitors reduce the conversion of testosterone to dihydrotestosterone, the hormone that drives prostate growth. By lowering DHT, these drugs slow or reverse prostate enlargement over months, reducing the static component of obstruction and lowering the risk of progression in men with larger prostates. Examples include finasteride and dutasteride.

Other drug classes aren’t considered first-line mainstays for BPH because they don’t target these two primary mechanisms: antibiotics treat infection; calcineurin or mTOR inhibitors are immunosuppressants; anticholinergics and PDE5 inhibitors may help with certain symptoms but don’t address both dynamic and static components as effectively as the combination of an alpha-blocker and a 5-alpha-reductase inhibitor.