Which medication class reduces prostate size over months in BPH?

• A. 5-alpha-reductase inhibitors
• B. Alpha-1 blockers
• C. Anticholinergics
• D. Antibiotics

Answer: (A)

Reducing prostate size in BPH hinges on interrupting the hormonal driver of prostatic growth. The growth in many men is fueled by dihydrotestosterone (DHT), which is formed from testosterone by the enzyme 5-alpha-reductase. When this enzyme is blocked, DHT levels fall, and the prostate slowly shrinks over several months. This is the action of 5-alpha-reductase inhibitors (such as finasteride and dutasteride). Over about 6 to 12 months, you’ll typically see a decrease in prostate volume and often a gradual improvement in symptoms related to obstruction.

In contrast, alpha-1 blockers relieve urinary symptoms quickly by relaxing smooth muscle in the bladder neck and prostate but do not reduce gland size. Anticholinergics address bladder overactivity, not gland growth, and antibiotics treat infection rather than volume. So the class that reduces prostate size over months is the one that blocks DHT production.