All are true about digoxin except:
**Core Concept**
Digoxin is a cardiac glycoside used in the treatment of heart failure and atrial fibrillation. It works by inhibiting the sodium-potassium ATPase pump, which increases the contractility of the heart muscle and slows the heart rate.
**Why the Correct Answer is Right**
Digoxin exerts its effects by binding to the Na+/K+-ATPase pump in cardiac cells, which leads to an increase in intracellular sodium and a subsequent increase in intracellular calcium. This increase in calcium leads to an increase in the contractility of the heart muscle. Additionally, digoxin can also slow the heart rate by increasing the vagal tone.
**Why Each Wrong Option is Incorrect**
**Option A:** Digoxin is primarily eliminated by the kidneys, and its clearance is reduced in patients with renal impairment.
* Incorrect because: While it's true that digoxin is primarily eliminated by the kidneys, this statement is incomplete and doesn't address the question.
**Option B:** Digoxin toxicity can be treated with digoxin-specific antibody.
* Incorrect because: This statement is true, not false.
**Option C:** Digoxin can cause a rise in serum potassium levels.
* Incorrect because: Digoxin actually can cause a drop in serum potassium levels due to increased cellular uptake.
**Option D:** Digoxin is contraindicated in patients with Wolff-Parkinson-White (WPW) syndrome.
* Incorrect because: This statement is true, not false.
**Clinical Pearl / High-Yield Fact**
Digoxin toxicity can manifest with symptoms such as nausea, vomiting, and visual disturbances. In severe cases, it can lead to cardiac arrhythmias and even death. It's essential to monitor patients on digoxin therapy closely for signs of toxicity, especially in patients with renal impairment or electrolyte imbalances.
**Correct Answer: D. Digoxin is contraindicated in patients with Wolff-Parkinson-White (WPW) syndrome.**