Essential hypertension. Matching pathophysiology and pharmacology.

The underlying pathophysiologic mechanisms that elevate arterial pressure differ according to the patient's age, adipose body mass, and race. However, these mechanisms represent the extremes of a continuum, and overlap among them can be encountered in some patients. A few simple clinical clues allow the physician to identify whether an increase in cardiac output, total peripheral resistance, or both is the predominant mechanism in a given patient. Antihypertensive therapy should be aimed not only at lowering arterial pressure but also, more importantly, at ameliorating the concomitant pathophysiologic abnormality. A beta-adrenoreceptor blocker is the initial drug of choice in young patients with "cardiogenic hypertension." In middle-aged patients, cardiac output is usually normal and elevated total peripheral resistance becomes the hemodynamic culprit. In these patients, an angiotensin-converting enzyme (ACE) inhibitor, antiadrenergic drug, or calcium channel blocker should be given to lower total peripheral resistance without affecting cardiac output. In elderly patients, the burden on the heart should be lessened by use of an agent that lowers preload and afterload, such as an ACE inhibitor or certain of the calcium blockers. In obese patients in whom intravascular volume is expanded and in most black patients, the initial antihypertensive agent of choice remains a thiazide diuretic unless left ventricular hypertrophy is present.