PHARMACOKINETICS OF EXOGENOUS ADENOSINE IN MAN AFTER INFUSION

The plasma kinetics of adenosine was investigated in healthy volunteer s after a 1 minute infusion of 2.5,5 and 10 mg (38,79 and 148 mug . kg -1 respectively) and after infusion of 200 mug . kg-1 in 10 min follow ed by 400 mug . kg-1 in 10 min. As the dose in the 1 min infusion stud y was increased the mean CL of adenosine decreased (10.7, 4.70 and 4.1 4 1 . min-1, respectively), its mean half-life increased (0.91, 1.24 a nd 1.86 min, respectively), and the mean volume of distribution did no t show any clear trend (8-13 1). After the 20 minute infusion the plas ma level of adenosine reached a peak value comparable to that observed after infusion of 5 mg in 1 min (about 0.5 mug . ml-1), but the mean clearance and half-life were significantly different (12.11 . min-1 an d 0.63 min respectively). In all the subjects the plasma concentration of adenosine had returned to the baseline value in 5-15 min after the end of the infusion.