Hypertension is a major therapeutic challenge to health care providers. It is a major risk factor for cardiovascular morbidity, heart failure, heart attack, stroke, and kidney failure.
Anti-hypertensive therapy is effective in reducing or eliminating the increased morbidity/mortality associated with hypertension. Hypertension is an asymptomatic disease for many years. Approximately 50 million people in the United States have high blood pressure.
Measuring Blood Pressure
The blood pressure should be taken with the subject seated and relaxed, and with the arms suitably bared. Avoid extraneous factors that may alter the blood pressure, such as:
Purposes of Clinical Evaluation
In the clinical evaluation of a patient with confirmed hypertension, the physician should:
- coarctation of the aorta
- chronic renal disease
- renovascular disease
- primary aldosteronism
- Cushing's syndrome
- intracranial lesions
- estrogens/oral contraceptives, steroidal and non-steroidal anti-inflammatory agents, nasal decongestants, appetite suppressants, and the tricyclic antidepressants
- excessive alcohol intake.
- diabetes mellitus
- physical inactivity
- family history.
A medical history should include the following:
The following baseline laboratory tests should be obtained before initiating therapy:
Additional diagnostic procedures may be indicated to discover secondary hypertension in patients:
Programs for the primary prevention of hypertension are currently being developed, implemented, and evaluated. These programs involve either the general population (population strategy) or a population of patients at risk for the development of hypertension (targeted strategy).
These programs are attempting to keep patients from developing hypertension by changing behaviors associated with becoming hypertensive. Life-style modifications that have shown promise in the primary prevention of hypertension have targeted persons with a high sodium intake, an excessive caloric intake, physical inactivity, excessive alcohol consumption, and a low potassium intake.
Community programs may become an important strategy for the primary prevention of hypertension and for monitoring progress and encouraging compliance in persons with hypertension.
The goal of hypertensive treatment is to prevent morbidity and mortality
associated with high blood pressure.
Most patients with persistent systolic levels above 160 mmHg and/or diastolic levels above 95 mmHg should receive antihypertensive therapy. Some experts believe that drug therapy should be initiated if the diastolic pressure remains above 90 mmHg despite vigorous attempts with non-pharmacologic measures, this being especially true in those with other significant risk factors.
Target blood pressure is less than 140/90.
The decision as to which drug to use first can usually be made on the basis of age, race, the presence of other medical problems, side effects, long-term safety, and cost. If one drug is found to be well-tolerated but only partially effective, the addition of a second drug of another class is rational. Half or more of patients will probably require a second drug, and about 10% will require three.
Because diuretics and á-blockers have been shown to reduce cardiovascular morbidity and mortality in controlled clinical trials, these two classes of drugs are preferred for initial drug therapy.
This recommendation from the JNC V report counters previous trends away from these agents because of the potential for adverse effects on lipid and glucose metabolism.3
Alternative drugs recommended for monotherapy include the calcium antagonists, angiotensin-converting enzyme (ACE) inhibitors, d-1 receptor blockers, and the d-á-blocker.
Although these alternative drugs have potentially important benefits, they have not been used in long-term controlled trials to demonstrate their efficacy in reducing morbidity and mortality, and therefore should be reserved for special indications or when diuretics and á-blockers have proved unacceptable or ineffective.
The d2-agonist, Clonidine, tends to produce annoying side-effects in a large number of patients and is not recommended for monotherapy. Clonidine is commonly used for monotherapy and in combination with other agents in LSU-S clinics because of its low cost.
Aspects of Medication Pharmacology
Certain aspects of medication pharmacology are particularly important in gaining long-term patient adherence to medication. These include:
The physician should stress the following points with the patient:
Appreciation is expressed to the JNC IV and V, major sources of the information contained herein.
The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure The Fifth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC V). Arch Intern Med 1993;153. Treatment of Hypertension: A Current Perspective. The Newspaper of Cardiology, June 1990. New Insights and New Approaches for the Treatment of Essential Hypertension. Mark C. Houston, M.D. American Heart Journal, p. 911-951, April 1989.