Treatment of HBP is usually directed at the cause of the HBP if it is known, for example, removal of tumors releasing catecholamines and correcting renal artery stenosis. If HBP is due to primary aldosteronism, then surgical removal of the tumor, or use of an ARA is usually effective (5,6). When the cause of the HBP is not known, traditionally called essential hypertension, therapy today frequently involves drugs that interfere with the RAS (7), but until recently the addition of an ARA was not usually included. Recently studies by Epstein and others (8,9) have shown that the addition of an ARA to the drug management of what has been considered essential HPB can further reduce HBP by over 10 mmHg, thus suggesting that the addition of an ARA to the routine tools available to treat HBP is important. Although the mechanism by which this addition of an ARA lowers HBP is not clear, the obvious suggestion is that by blocking the effect of aldo on the kidney to reabsorb Na there is an increased excretion of Na which is responsible for the lowering of HBP.