Drug of choice for ventricular premature beats(VPB) with digitalis toxicity is
**Core Concept**
Digitalis toxicity is a condition where the effects of digitalis (a cardiac glycoside) become harmful to the body. This can occur due to an overdose, kidney or liver problems, or other underlying conditions. The drug of choice for treating ventricular premature beats (VPBs) with digitalis toxicity is a medication that can counteract the toxic effects of digitalis without exacerbating the condition.
**Why the Correct Answer is Right**
The drug of choice for ventricular premature beats (VPBs) with digitalis toxicity is **phosphodiesterase inhibitors**, such as **amrinone** or **milrinone**. These medications work by inhibiting the phosphodiesterase enzyme, which breaks down cyclic AMP (cAMP) in the heart. By increasing cAMP levels, these drugs can help to counteract the toxic effects of digitalis on the heart, including its negative inotropic effects (reduced contractility). Additionally, phosphodiesterase inhibitors can increase heart rate and contractility, which can help to control VPBs.
**Why Each Wrong Option is Incorrect**
**Option A:** **Beta-blockers** are not the best choice for treating VPBs with digitalis toxicity, as they can further reduce heart rate and contractility, exacerbating the condition.
**Option B:** **Calcium channel blockers** can also worsen digitalis toxicity by further reducing contractility and heart rate.
**Option C:** **Magnesium sulfate** can be used to treat digitalis toxicity, but it is not the primary treatment for VPBs.
**Clinical Pearl / High-Yield Fact**
When treating digitalis toxicity, remember that phosphodiesterase inhibitors like amrinone or milrinone can be used to counteract the toxic effects of digitalis on the heart, while beta-blockers and calcium channel blockers should be avoided.
**Correct Answer:** C. Magnesium sulfate