What is the onset time for Adenosine when administered?

The onset time for Adenosine is considered to be immediate. When administered intravenously, Adenosine reaches the bloodstream very quickly, leading to rapid pharmacological effects. This is particularly significant in emergency settings, such as the treatment of certain types of supraventricular tachycardia, where a quick response is essential to restore normal heart rhythm. The almost instantaneous effect of Adenosine is a key reason it's often utilized in acute cardiac situations. Other options suggest a delay in onset, which does not align with the pharmacokinetics of Adenosine.