## **Core Concept**
Gynaecomastia is the enlargement of breast tissue in males, often caused by an imbalance of sex hormones, specifically an increase in estrogen relative to testosterone. Various pharmaceutical agents can disrupt this balance, leading to gynaecomastia.

## **Why the Correct Answer is Right**
The correct answer, , is associated with a mechanism that does not typically lead to gynaecomastia. To understand this, we need to examine the effects of each listed pharmaceutical agent on hormone levels or their direct effects on breast tissue.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Certain drugs like **spironolactone** (a potassium-sparing diuretic) can cause gynaecomastia due to its anti-androgenic effects, blocking testosterone receptors.
- **Option B:** **Digitalis** and its derivatives can cause gynaecomastia, though the mechanism is less clear; it's thought to be related to estrogenic effects.
- **Option C:** Some **antidepressants**, particularly **selective serotonin reuptake inhibitors (SSRIs)**, have been associated with gynaecomastia, possibly due to their effects on hormone levels.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that gynaecomastia can be caused by a wide range of drugs, including anabolic steroids (paradoxically, both testosterone and estrogen imbalances can lead to gynaecomastia), certain antibiotics, and antihypertensive drugs. When evaluating gynaecomastia, a thorough drug history is essential.

## **Correct Answer:** .