The effect of prindolol on plasma noradrenaline, plasma renin and sodium-potassium metabolism in patients with essential hypertension.

The chronic administration of prindolol in patients with essential hypertension resulted in the following: 1) a significant decrease in blood pressure and heart rate (with only the exception of the unchanged diastolic blood pressure after the stimulus of the seven-minute standing period), 2) a significant decrease of plasma noradrenaline concentrativn at rest and under orthostatic conditions, 3) a significant decrease of PRC at rest and an even more pronounced suppression of PRA after the stimulus of upright posture, 4)a significant decrease in total exchangeable sodium and 5) a concomitant significant increase in total body potassium even with an increase in body weight. These findings are not subject to easy interpretation. In particular, we cannot conclude which of the changed parameters plays the initial role in lowering blood pressure. A working hypothesis might presume that beta blocking agents inhibit central and/or peripheral sympathetic nervous activity. The results reduction in plasma renin concentration would in turn lead to a drop in aldosterone secretion rate indicated by the increase in potassium and decrease in sodiummour data would support such a sequence of events.