**Question:** All of the following statements about amiloride are true EXCEPT:

A. Amiloride is a diuretic that increases urine output and reduces blood pressure.
B. Amiloride competitively inhibits the epithelial sodium channel (ENaC) in the kidneys.
C. Amiloride inhibits the sodium pump (Na+/K+-ATPase) in the kidneys.
D. Amiloride is commonly used as a medication for high blood pressure.

**Correct Answer:** C. Amiloride inhibits the sodium pump (Na+/K+-ATPase) in the kidneys.

**Core Concept:** Amiloride is a medication primarily used for the management of hypertension and edema associated with heart failure or kidney disease. Amiloride exerts its effects through the inhibition of the epithelial sodium channel (ENaC) and the sodium pump (Na+/K+-ATPase) in the kidneys.

**Why the Correct Answer is Right:** Amiloride is a potassium-sparing diuretic, which means it prevents the loss of potassium from the body and helps to reduce blood pressure by promoting the excretion of excess sodium and water, thus decreasing blood volume and blood pressure. The drug specifically inhibits the epithelial sodium channel (ENaC) in the kidneys, preventing sodium reabsorption and promoting sodium and water excretion.

**Why Each Wrong Option is Incorrect:**

A. Amiloride is a potassium-sparing diuretic, not increasing urine output or reducing blood pressure. It does, however, help to manage hypertension and edema.

B. Amiloride does inhibit the sodium pump (Na+/K+-ATPase) in the kidneys, but this is not the primary mechanism of action for amiloride in hypertension management.

C. This statement is incorrect because amiloride does not inhibit the sodium pump (Na+/K+-ATPase) in the kidneys. Instead, it primarily targets the epithelial sodium channel (ENaC) for its therapeutic effect.

D. Amiloride is primarily used for hypertension management, not specifically for high blood pressure treatment. While it can be helpful for managing high blood pressure, its primary indication is to reduce edema associated with heart failure or nephrotic syndrome.

**Clinical Pearl:** In the context of hypertension management, amiloride's primary mechanism involves inhibiting the epithelial sodium channel (ENaC) in the kidneys, leading to reduced sodium and water reabsorption. The drug is primarily used to manage edema associated with conditions like heart failure or nephrotic syndrome. While it can be beneficial in reducing blood pressure, its main therapeutic focus is on reducing fluid retention.