An old man is having benign prostatic hyperophy. Which of the following drug is used to reduce the size of prostate in such a person?
**Core Concept**
Benign prostatic hyperplasia (BPH) is a non-cancerous enlargement of the prostate gland, often associated with aging males. The condition is characterized by an increase in the size of the gland's stromal and epithelial components, leading to urinary retention and other lower urinary tract symptoms.
**Why the Correct Answer is Right**
The correct answer is Finasteride, a 5-alpha-reductase inhibitor (5-ARI). Finasteride works by inhibiting the enzyme 5-alpha-reductase, which is responsible for converting testosterone to dihydrotestosterone (DHT). DHT is a potent androgen that promotes the growth of prostate tissue. By reducing DHT levels, Finasteride decreases the size of the prostate gland and alleviates symptoms of BPH.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the treatment of BPH. Phosphodiesterase inhibitors, such as tadalafil, are used to treat erectile dysfunction (ED) and benign prostatic hyperplasia (BPH) symptoms, but they do not reduce prostate size.
**Option B:** This option is incorrect because alpha-blockers, such as doxazosin, are primarily used to treat the symptoms of BPH, such as urinary retention and frequency, by relaxing smooth muscle in the prostate and bladder neck. They do not reduce prostate size.
**Option C:** This option is incorrect because 5-HT3 receptor antagonists, such as ondansetron, are primarily used to prevent nausea and vomiting. They are not used to treat BPH or reduce prostate size.
**Option D:** This option is incorrect because beta-2 agonists, such as albuterol, are primarily used to treat asthma and chronic obstructive pulmonary disease (COPD). They are not used to treat BPH or reduce prostate size.
**Clinical Pearl / High-Yield Fact**
Finasteride is a first-line treatment for BPH, and it is essential to note that it may take 6-12 months to observe significant reductions in prostate size and symptom improvement. Additionally, patients with a history of prostate cancer or those with a high risk of prostate cancer should not use Finasteride.
**Correct Answer:** C.