INCREASE IN PLASMA-LEVELS OF ADENOSINE AND ADENINE-NUCLEOTIDES AFTER INTRAVENOUS-INFUSION OF BUFLOMEDIL IN HUMANS

To clarify the mode of action of the vasoactive agent buflomedil, we evaluated plasma levels of adenosine and adenine nucleotides after intravenous (i.v.) infusion in humans of 50, 100, and 200 mg of the drug in 20 min. Buflomedil induced an increase of the same order of magnitude in plasma levels of adenosine and adenine nucleotides. Maximal adenosine increase (84%) was observed at the end of the infusion period, whereas peak plasma levels of ATP and ADP (69 and 55%, respectively) and of AMP (61%) were detected 10 and 5 min after discontinuation of infusion, respectively. Although the exact mode of action of buflomedil at the molecular level remains unclear, some indirect findings suggest that the increase in adenosine may be due to enhanced release rather than to inhibition of cell uptake. Because such activity of buflomedil consists of enhancement of physiologic mechanisms of vasodilation and tissue protection occurring in the course of ischemic events, new pharmacologic perspectives for the drug may arise.