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 ADENOSINE BRAND NAME:- ADENOJECT, ADENOCOR 3mg adenosine (base) per ml in 2ml and 10ml amp. ADENOSINE administered by rapid i.v injection (over 1-3sec) either as the free base (6-12mg) or as ATP(Adenosine triphosphate) (10-20mg) , Adenosine terminates with in 30sec. More than90% episodes of PSVT involving the A-V node.it activated ACh sensitive K+ channels and causes membrane hyperpolarization through interaction with A1 type of Adenosine GPCRs on SA node (pacemaker depression ~bradycardia ), A-V node (prolongation of ERP--slowing of conduction ) and atrium (shortening of AP, reduced excita-bility). It indirectly reduces Ca2+ current in A-V node. Depression of the reentrant circuit through A-V node is responsible for termination of majority of PSVTs. Adrenergically  induced DADs(delayed after -depolarization) in ventricle are also suppressed. Coronary dilatation occurs transiently. ACTION:-adenosine has a very short T1/2 in blood (~10sec) due to uptake into RBCs and endotheli...