Question:medium
Drug which decreases efficacy of testosterone?
Drug which decreases efficacy of testosterone?
Show Hint
An azole antifungal that blocks P450 steroid-synthesis enzymes and acts as an anti-androgen.
Updated On: Jun 24, 2026
- Isoniazid
- Ketoconazole
- Rifampicin
- None
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: We need the agent that lowers the biological effect of testosterone.
Step 2: The male hormone is built from cholesterol via a cascade of cytochrome P450 catalysed reactions in the testis and adrenal cortex.
Step 3: Ketoconazole, an imidazole antifungal, is a potent blocker of these steroidogenic P450 enzymes (notably 17-alpha-hydroxylase and 17,20-lyase). Shutting down these enzymes cuts androgen production, so circulating testosterone and its effect fall. This anti-androgenic property is exploited clinically to suppress testosterone in hormone-driven prostate cancer.
Step 4: The antitubercular drugs isoniazid and rifampicin are not the expected answer; therefore the correct choice is ketoconazole.
\[\boxed{Ketoconazole}\]
Step 2: The male hormone is built from cholesterol via a cascade of cytochrome P450 catalysed reactions in the testis and adrenal cortex.
Step 3: Ketoconazole, an imidazole antifungal, is a potent blocker of these steroidogenic P450 enzymes (notably 17-alpha-hydroxylase and 17,20-lyase). Shutting down these enzymes cuts androgen production, so circulating testosterone and its effect fall. This anti-androgenic property is exploited clinically to suppress testosterone in hormone-driven prostate cancer.
Step 4: The antitubercular drugs isoniazid and rifampicin are not the expected answer; therefore the correct choice is ketoconazole.
\[\boxed{Ketoconazole}\]
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