Active metabolite of Spironolactone is:
**Core Concept**
Spironolactone is a potassium-sparing diuretic that acts as a competitive antagonist of the mineralocorticoid receptor. The active metabolite plays a crucial role in the clinical efficacy of the drug.
**Why the Correct Answer is Right**
Spironolactone undergoes extensive hepatic metabolism, primarily through the CYP3A4 enzyme, to form its active metabolite, canrenone. Canrenone is a potent antagonist of the mineralocorticoid receptor, which contributes to its diuretic and antihypertensive effects. The conversion of spironolactone to canrenone occurs via hydroxylation, resulting in a compound with increased receptor affinity and duration of action.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not accurately represent the active metabolite of spironolactone.
* **Option B:** This option is incorrect because it is not a known metabolite of spironolactone.
* **Option D:** This option is incorrect because it is not a metabolite of spironolactone.
**Clinical Pearl / High-Yield Fact**
It is essential to note that spironolactone's efficacy is not solely dependent on its plasma concentration but also on its active metabolite levels. Therefore, monitoring canrenone levels can provide valuable insights into the drug's effectiveness and potential side effects.
**Correct Answer: C. Canrenone**