Adenosine dose should be less when administered through a central line.

A patient with a port-a-cath was given 12 mg of adenosine for paroxysmal supraventricular tachycardia (PSVT), resulting in prolonged (13 s) bradycardia and severe side effects. When the same patient presented 2 weeks later for recurrent PSVT, only 3 mg of adenosine was needed to terminate the episode, without the patient experiencing prolonged bradycardia or severe side effects. The literature suggests that for patients with central venous catheters, a lower dose of adenosine should be used to terminate PSVT.