Drug of choice for Digoxin induced Ventricular Tachycardia:
**Core Concept**
Digoxin-induced ventricular tachycardia is a potentially life-threatening arrhythmia caused by digitalis toxicity. The drug of choice for treating this condition involves a medication that can effectively counteract the cardiac effects of digoxin.
**Why the Correct Answer is Right**
The correct answer is a beta-blocker, specifically **Labetalol**. Labetalol is a non-selective beta-blocker that can help reduce the heart rate and contractility caused by digoxin toxicity. This is achieved by blocking the beta-1 receptors in the heart, which are responsible for increasing heart rate and contractility. Additionally, labetalol has a mild vasodilatory effect, which can help decrease the cardiac workload and reduce the risk of further arrhythmias.
**Why Each Wrong Option is Incorrect**
**Option A:** **Magnesium Sulfate** is often used to treat torsades de pointes, a specific type of ventricular tachycardia, but it is not the first-line treatment for digoxin-induced ventricular tachycardia.
**Option B:** **Phenobarbital** is a barbiturate that can be used to treat seizures, but it is not effective in treating arrhythmias caused by digoxin toxicity.
**Option C:** **Phenylephrine** is a selective alpha-1 agonist that can cause vasoconstriction and increase cardiac workload, which is the opposite of what is needed in this situation.
**Clinical Pearl / High-Yield Fact**
In cases of digoxin toxicity, always consider the possibility of a "digitalis effect" on the heart, which can manifest as arrhythmias, bradycardia, or heart block.
**Correct Answer:** C. Phenylephrine