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• Stress.


• Diet.


• Excessive smoking and alcohol ingestion.

There are three stages of hypertension. Along with normal blood pressure

(systalic and distalic) these are

1.Normal <120 and <80

2.Pre-hypertension: 120–129/80–89 mm Hg.

3.Stage 1 hypertension: 140–159/90–99 mm Hg.

4.Stage 2 hypertension: at or greater than 160–179/100–109 mm Hg.

KIDNEYS AND BLOOD PRESSURE

The kidneys use the renin-angiotensin system to maintain blood pressure. The

renin-angiotensin system increases blood pressure by retaining sodium and

water. Once baroreceptors in the aorta and carotid sinus detect adequate blood

pressure, the baroreceptors signal the vasomotor center in the medulla to signal

the renin-angiotensin system to excrete sodium and water, thereby lowering the

blood pressure.

Hypertension is treated using a stepped-care approach. Each step uses a differ-

ent group of antihypertensive drugs to control hypertension. There are four steps.

Step 1: Diuretic, beta blocker, calcium blocker, angiotensin-converting

enzyme (ACE)

Step 2: Diuretic with beta blocker, sympatholytics

Step 3: Direct-acting vasodilator; sympatholytic with diuretic

Step 4: Adrenergic neuron blocker; combinations from Steps 1, 2, and 3.

COMBINING ANTIHYPERTENSIVE DRUGS

An antihypertensive drug can be used alone or in combination with one or more

drugs that fall into one of five categories.

Diuretics

Diuretics promote sodium depletion, which decreases extracellular fluid volume.

It is the first-line drug for treating mild hypertension. Hydrochlorothiazide

(^356) CHAPTER 19 Cardiac Circulatory Medications