The paramedics gave it to me twice (I believe 6 mg each time) and the Emergency Room doctor gave it to me two more times (I believe 6
mg and then 12
mg) -- a total of four times during one episode. Adenosine stopped my heart briefly, except for a little blip, but the rapid heart beat immediately returned. Others praise adenosine; it did no good at all for me. I am now taking Diltiazem (120 mg), and I don't think it is working.