Normal Control of Blood Pressure

Although the control of blood pressure is a fairly complex subject, the actual factors that determine blood pressure can be simplified. At any given time, blood pressure is the product of cardiac output and the total resistance in the peripheral vasculature. This relationship is illustrated by the following equation  

The relevance of this simple equation to antihypertensive therapy will become apparent as different drugs are discussed. Some antihypertensive drugs exert their effects by primarily acting on CO, others primarily affect TPR, and some agents decrease both factors. 

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