Final answer:
Lidocaine is the drug most commonly used to treat ventricular tachycardia. It works by blocking sodium channels in the heart to restore a normal heart rhythm.
Step-by-step explanation:
The drug most commonly used to treat ventricular tachycardia is lidocaine. Lidocaine is a class I antiarrhythmic medication that works by blocking sodium channels in the heart, inhibiting the abnormal electrical signals that can cause ventricular tachycardia. It is often administered intravenously in emergency situations to quickly restore a normal heart rhythm.