Prescribing Safety Assessment (PSA) Practice Exam

Which anti-hypertensive is known to cause gynaecomastia?

1. Beta blockers

2. Calcium channel blockers

3. Potassium-sparing diuretics

4. ACE inhibitors

The correct answer is: Potassium-sparing diuretics

Potassium-sparing diuretics, particularly spironolactone, are known to cause gynaecomastia as a side effect. This condition results from the anti-androgenic effects of spironolactone, which can lead to altered hormone levels, specifically interfering with the normal balance of testosterone and estrogen. The accumulation of estrogenic activity from this disruption can promote breast tissue growth, hence leading to gynaecomastia. While other classes of antihypertensives like beta blockers, calcium channel blockers, and ACE inhibitors may have their own side effects, they are not commonly associated with gynaecomastia. Beta blockers can sometimes lead to sexual dysfunction or fatigue, for example, but they do not have the same hormonal influence as potassium-sparing diuretics. Understanding the specific mechanisms of each medication is essential in recognizing potential side effects like gynaecomastia.