Dipyridamole decreases circulating renin-angiotensin system activity in hypertensive patients

To study the effect of adenosine on renin release, n = 6 hypertensive patients, while on a constant 80 to 100 mEq/24 h Na+ diet, received oral 150 mg dipyridamole (an adenosine uptake inhibitor) three times daily for 3 days while upright plasma renin activity (PRA) and plasma aldosterone, urinary aldosterone, plasma and urinary Na+,K+, and creatinine clearance were monitored the day before (basal) the first and third day of the treatment and the day after the withdrawal (recovery). As compared to basal and to recovery, dipyridamole significantly decreased PRA, and plasma and urinary aldosterone without affecting plasma and urinary Na+ and K+, creatinine clearance, blood pressure, and heart rate. These data, showing that dipyridamole decreases PRA and aldosterone, confirm also in hypertensives that endogenous adenosine inhibits the circulating renin-angiotensin-aldosterone system.