Antihypertensive drug treatment is effective in only about 50% of patients. One mechanism
responsible for treatment failure is a drug related stimulation of the
renin-angiotension-aldosterone-system (RAAS). Several classes of medications that treat
hypertension by blocking the RAAS system have been developed. However, the kidney responds to
these drug treatments by producing greater amounts of renin. This high level of renin can
reduce the effectiveness of some of these medications, ultimately causing the blood pressure
to rise. This is one reason why blood pressure can be difficult to control in a certain
percentage of patients.
The hypothesis to be tested in the proposed study is that beta-adrenergic blockade
(β-blockade), when superimposed upon aliskiren, a drug that competitively inhibits plasma
renin activity (PRA) but stimulates the release of renin by the kidneys (plasma renin
concentration [PRC]), can suppress the reactive increase in PRC that occurs during aliskiren
monotherapy.
The primary aim of this study is to measure plasma renin concentration (PRC) and plasma renin
activity (PRA) levels during renin inhibition with aliskiren and combined renin
inhibition/β-blocker treatment to determine whether the addition of a β-blocker attenuates
the rise in plasma renin concentration (PRC). A secondary aim is to determine whether
combined treatment further suppresses PRA and blood pressure.