Digoxin is used for treatment of congestive hea failure. It acts by inhibiting:-
**Core Concept**
Digoxin is a cardiac glycoside used in the management of congestive heart failure (CHF) and atrial fibrillation. It works by modulating the activity of the sodium-potassium ATPase pump in cardiac cells.
**Why the Correct Answer is Right**
Digoxin inhibits the sodium-potassium ATPase pump, leading to an increase in intracellular sodium levels. This increases the activity of the sodium-calcium exchanger, which pumps calcium ions into the cardiac cells. The increased intracellular calcium levels enhance the contractility of the heart muscle, improving cardiac output in CHF patients. Additionally, digoxin also has a vagolytic effect, which helps to slow the heart rate in atrial fibrillation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as digoxin does not act by inhibiting the angiotensin-converting enzyme (ACE).
**Option B:** This option is incorrect as digoxin does not act by inhibiting the beta-adrenergic receptors.
**Option C:** This option is incorrect as digoxin does not act by inhibiting the phosphodiesterase enzyme.
**Clinical Pearl / High-Yield Fact**
Digoxin has a narrow therapeutic index and requires close monitoring of serum levels to prevent toxicity, which can manifest as nausea, vomiting, and arrhythmias.
**Correct Answer: C. sodium-potassium ATPase pump.**