Treatment of Hypertension

One of the more difficult decisions in medicine is how to treat hypertension. Though a potentially life-threatening—certainly a life-shortening—disease, in most patients hypertension is consistent with good general health. Yet a diagnosis of hypertension may require a commitment on the part of the patient to lifelong use of one or more drugs that frequently produce undesirable side effects—to put it bluntly, may make a well person sick. Consequently, before the initiation of antihypertensive therapy some questions need to be considered. Can the patient safely be left untreated? Could nonpharmacological treatment be effective? Could the patient have one of the rare curable varieties of hypertension that can be eliminated by a surgical intervention?

Differentiating between normal variations in blood pressure with unusual overshoots and true hypertension is difficult. This fact, together with observations showing that serious consequences of hypertension are mostly found in severe hypertension, has led to a controversy regarding the treatment of mild hypertension (diastolic pressure averaging less than 105 mm Hg). Some experts recommend treatment even in the mildest cases of hypertension; others favor postponing therapy, while maintaining careful supervision, unless the patient enters the stage of moderate hypertension. More often, however, early treatment of mild hypertension is advised. Antihypertensive therapy is tailored to each patient according to the degree of hypertension and the patient's motivation in adhering strictly to instructions involved in drug therapy.

Before starting therapy, the patient undergoes a careful evaluation to determine the extent of damage to body organs from the existing hypertension. If an abnormal electrocardiogram or echocardiogram demonstrates left ventricular hypertrophy, abnormalities of the vessels in the eye or impaired kidney function, aggressive therapy is mandatory, even if hypertension is only mild at the time of discovery. In cases of mild hypertension nonpharmacological therapy is tried first; such treatment is most successful in this group of patients. It includes reducing sodium (salt) in the diet, reducing body weight if the patient is overweight, avoiding stressful situations, engaging in recreational activities, and establishing a regular exercise program.

Only 2 percent of the cases of hypertension are curable. Certain screening tests may suggest such a possibility and justify more-elaborate studies. The search for reversible secondary hypertension is usually limited to cases in which unusual findings are present, such as severe or rapidly progressive hypertension in young persons; in addition, certain syndromes atypical of essential hypertension may point to some underlying disease responsible for the hypertension.

Most patients treated for hypertension are apparently healthy and asymptomatic persons with mild or moderate hypertension who are committed to prolonged drug therapy. Since the introduction of effective antihypertensive drugs in the 1950s, nearly 50 different drugs have been approved for treatment of hypertension, and the number of new drugs is constantly increasing.

Drugs are classified according to their effect on a specific function involved in regulating blood pressure. Most drugs in each class have similar—often identical—action and can be used interchangeably, although manufacturers often claim the superiority of one drug over the others. The important categories of antihypertensive drugs are

diuretics, which enhance salt excretion

drugs reducing or blocking vascular control exerted by the sympathetic nervous system

drugs dilating arterioles and thereby reducing resistance (and pressure)

drugs blocking the flow of calcium into cells

drugs inhibiting the angiotensin-converting enzyme

Antihypertensive therapy demands collaboration between physician and patient. To begin, one of the "first-line" antihypertensive agents least likely to have side effects is usually administered and the dose adjusted according to its effectiveness. Undesirable side effects may require switching to a drug from another class. Large doses of a single drug are often avoided in favor of adding a second drug. In severe hypertension or drug-resistant hypertension it may be necessary to use a combination of several drugs. Success in such therapy is gauged by the patient's tolerance for drugs and the

effective reduction of blood pressure. Patients who tolerate drugs poorly may have to settle for more-modest therapeutic goals, such as reducing moderate or severe hypertension to mild hypertension. Whereas in most cases effective and well-tolerated drugs can be found easily, in drug-resistant patients a prolonged period of drug testing by trial and error may be necessary.