December 20th, 2009 
admin Brief about High Blood Pressure
Blood pressure is measure of pressure exerted by circulating blood against the walls of vessels. Contraction of blood carrying arteries, capillaries and vessels cause high blood pressure. Increase in blood pressure mean increase of work load on heart. If this happens and stays for long time it can lead to serious health conditions such as strokes, heart failure, heart attacks, arterial aneurysm and chronic renal failure.
What causes High Blood Pressure?
ACE
: ACE (angiotensin converting enzyme) is naturally occurring protein in body. ACE is responsible to produce angiotensin II which contracts arteries of hearts and kidneys. This results in more pressure on arteries wall.
Impurities in Blood
: Fluid, small substances, electrolytes are filtered by kidneys when blood flows through. Such impurities are mostly reabsorbed and gets back into blood.
There are many drugs available in market to control high blood pressure. Different drugs work in different ways to bring high blood pressure back to normal. Depending upon mechanism of action antihypertensive drugs is classified in six classes. This reading explains in brief about each of the classes.
Anti Hypertension Drugs
ACE Inhibitor Drugs
High blood pressure controlling drugs of this class acts on ACE (Angiotensin Converting Enzyme) and block its activity. ACE, mainly found in lungs and brain, produce Angiotensin II. Angiotensin II narrows arteries, through which blood flows. This increase pressure of blood on artery walls against which heart has to pump (in this case needs hard pumping) blood. An ACE inhibitors drug lowers production of Angiotensin II by inhibiting ACE activity.
Diuretic Drugs
As said earlier, reabsorbtion of filtered impurities of the blood into the nephrons of the kidneys leads to high blood pressure. Diuretic high blood pressure drugs blocks reabsorbtion by increasing the amount of urine to be eliminated from the body.
All diuretics drugs acts on kidneys but works at different places inside kidneys.
Diuretics that work at loop of Henle are called loop diuretics
Potassium-sparing diuretic are second type of diuretic and they work in collecting ducts located inside kidneys.
Diuretics are called thiazide diuretics as their site of activity is in distal tubule.
Angiotensin II Receptor Blocker Drugs
Drugs of class Angiotensin II Receptor Blocker Drugs are called AT1-receptor antagonists. These drugs block receptors which are needed to activate angiotensin II. Blocking activity of receptors stop activation of angitensin II, help vasodilation (broadning areteries, capillaries and veins) and production of aldosterone which eventually reduces blood pressure.
Beta Blocker Drugs
Selective Adrenergic Beta receptors blockers are indicated for high blood pressure, heart pain, abnormal heart rate and for recovery after heart attack. This class of high blood pressure drugs blocks acts of sympathetic nervous system thereby help to bring heart beat rate to normal rate. Beta blockers reduce the force of contraction of heart muscle which helps to bring high blood pressure back to normal.
Calcium Channel Blocker Drugs
Calcium channel blockers blocks voltage-gated calcium channels of within heart arteries and blood vessels. Higher amount of calcium cause more contraction of heart muscles. Inhibiting calcium results in relaxation of arteries and blood vessels and eventually leads to reduce high blood pressure.
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