Monday April 12, 2010


Q: 51 year old male with previous history of Asthma presented to ER with frequent episodes of supra-ventriculat tachycardia (SVT). As you enter patient's room you are amused by the fact that though heart rate on monitor is 180/minutes patient is drinking a cup of coffee.You administered adenocard twice with maximum dose but there is no response. What could be the reason?



Answer: Patient has history of Asthma and could be on theophylline. Also, patient's intake of caffeine may be masking the effect of Adenosine.

Theophylline/aminophylline antagonize actions of Adenocard. Another major culprit could be caffeine. By nature of caffeine's purine structure it binds to some of the same receptors as adenosine. The pharmacological effects of adenosine may therefore be blunted in individuals who are taking large quantities of methylxanthines (e.g., caffeine, found in coffee and tea, or theobromine, as found in chocolate).