Pharmacokinetics of exogenous adenosine in man after infusion

The plasma kinetics of adenosine was investigated in healthy volunteers after a 1 minute infusion of 2.5, 5 and 10 mg (38.79 and 148 micrograms.kg-1 respectively) and after infusion of 200 micrograms.kg-1 in 10 min followed by 400 micrograms.kg-1 in 10 min. As the dose in the 1 min infusion study was increased the mean CL of adenosine decreased (10.7, 4.70 and 4.14 l.min-1, respectively), its mean half-life increased (0.91, 1.24 and 1.86 min, respectively), and the mean volume of distribution did not show any clear trend (8-13 l). After the 20 minute infusion the plasma level of adenosine reached a peak value comparable to that observed after infusion of 5 mg in 1 min (about 0.5 micrograms.ml-1), but the mean clearance and half-life were significantly different (12.1 l.min-1 and 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.