Which drug can effectively terminate a refractory paroxysmal supraventricular tachycardia (PSVT)?

Adenosine is the preferred medication for the rapid termination of refractory paroxysmal supraventricular tachycardia (PSVT). It works by temporarily blocking the conduction through the atrioventricular (AV) node, leading to a rapid decrease in heart rate. This action can reset the electrical activity of the heart and restore a normal rhythm, making it particularly effective for treating PSVT, which is characterized by episodes of rapid heart rate originating above the ventricles.

This drug is usually administered intravenously and acts very quickly, often converting the rhythm within seconds. It is important to note that while other medications like verapamil and digoxin can also be used in the management of certain tachycardias, they are not as fast-acting or effective in the acute termination of PSVT as adenosine is.

Amiodarone, while being a versatile antiarrhythmic agent, is typically used for more complex arrhythmias or in situations where other causes of arrhythmia need to be controlled, rather than directly targeting PSVT in acute settings. Thus, adenosine's quick action and specific effectiveness against PSVT make it the drug of choice in this scenario.