Question

Finasteride is a:

• A. 5 alpha reductase inhibitor
• B. PDE inhibitor
• C. Alpha 1a blocker
• D. Androgen receptor blocker

Hint:

It blocks conversion of testosterone to dihydrotestosterone.

Answer 1

The Correct Option is A

Step 1: Finasteride is a competitive inhibitor of the enzyme 5-alpha reductase, which converts testosterone into the more potent androgen dihydrotestosterone (DHT).

Step 2: By lowering DHT, finasteride shrinks the prostate gland. In benign prostatic hyperplasia it reduces prostate volume and raises the peak urinary flow rate.

Step 3: Because DHT also drives scalp hair loss, finasteride is used in male pattern baldness, and it serves as palliative therapy in prostate carcinoma. So the answer is a 5-alpha reductase inhibitor.

Step 4: The distractors describe other drugs: PDE inhibitors are like sildenafil; alpha 1a blockers are like tamsulosin; and an androgen receptor blocker is like flutamide.