Antihypertensives are used to restore blood pressure (BP) in normal cases of hypertension. This class of drugs includes a large number of substances with diverse modes of action. When one drug is not sufficient to normalize blood pressure, two antihypertensive agents may be involved.
Blood pressure is the pressure exerted by blood in blood vessels, it is naturally regulated at different levels including renal, hormonal and nervous. This pressure varies depending on the rhythm of the heart. Represented by two digits (eg 14 / 8), represents the first blood pressure (BP) ie maximum blood pressure when the heart contracts (systole), the second blood pressure minimum prevailing in when the rest of the heart (diastole).
When can we speak of hypertension?
Blood pressure varies normal in many situations (stress, sleep, etc..). The criteria for diagnosis of hypertension should be checked before considering setting up a salary to be taken for life. The World Health Organization (WHO) has defined a protocol for measuring blood pressure which can highlight hypertension safely. In most cases, it is called hypertension when the first number exceeds 16 or when the second greater than 9.5 or both.
Except in severe cases, hypertension is a chronic disease more or less silent whose effects are observed after several years. It is therefore important to detect and treat. Treatment of hypertension is almost always introduced to life.
Beware of hypotension induced by treatment
According to their mode of action, anti-hypertensives can have different side effects and may interact with other substances. The side effects common to all is hypotension that is to say excessive reduction of blood pressure. This is particularly evident in the transition from sitting to standing position, this is called orthostatic hypotension. A reduction in dosage is usually sufficient to eliminate this side effect. The combination with other medicines that lower blood pressure may also cause hypotension.
No stop unwanted treatment
Besides the perpetual nature of anti-hypertensives, it is also important to know that in most cases, they should not be stopped so abruptly. Indeed, often, a crash can cause a severe increase in blood pressure and risk of complications. In short, we must never "barter" their treatment without first talking with your doctor.
The major classes of drugs:
By blocking certain receptors in the adrenergic system (called receptors alpha1-adrenergic receptors), these drugs cause dilation of blood vessels and thus a decrease in blood pressure. Less and less used, they are indicated in young patients with a history of depression, asthma, chronic bronchitis, diabetes, hyperlipidemia. In short, when other classes of antihypertensives are more or less cons-listed. Their main side effects are orthostatic hypotension may result in loss of consciousness, fluid retention synonymous with edema.
- The central anti-hypertensive
Their action is exerted mainly by stimulation of alpha2 adrenergic receptors. Unlike the alpha1-adrenergic receptors including inhibition lowers blood pressure, alpha2 receptors decreases blood pressure when stimulated. They are primarily prescribed for hypertension difficult to control. Side effects are sedation, constipation, dry mouth, depression. They are used in elderly patients suffering from hypertension complicated by kidney failure, asthma or diabetes.
These drugs work by blocking receptors involved in the increase of blood pressure: the beta-adrenergic receptors. They are mainly used in uncomplicated hypertension in young patients. They are cons-indicated in cases of asthma, Raynaud's syndrome, heart failure and certain disorders of cardiac conduction (atrioventricular block) and arteritis, etc.. Their main side effects include depression, impaired libido, Nightmares and fatigue.
They work by blocking a crossing patterns of calcium in cells. The decrease in cellular calcium that results causes a relaxation of arteries, decreased activity of the heart and thus a decrease in blood pressure. It is a class of antihypertensive quite heterogeneous. They are targeted primarily to elderly patients, the coronary, diabetes, obesity ... They are also useful during severe hypertension or poorly controlled by beta blockers, or secondary to primary aldosteronism, or associated with impotence, hyperlipidemia or hyperuricemia.
- Thiazide diuretics (kaliuretic)
They increase the natural process of removing water by the kidneys that lowers blood volume and made a drop in blood pressure. The main side effects are decreases in blood potassium (potentially very serious), glucose, cholesterol or uric acid (gout), orthostatic hypotension. They are widely used. They are more efficient than the subject is older and retain a very important role in the treatment of hypertension.
Like its predecessors, they promote the renal elimination of water but by a different mechanism. Indeed, they generally exert an action opposite to that of thealdosterone. They facilitate renal excretion of sodium (in favor of potassium) and water, which promotes a decrease in blood volume and blood pressure. Depending on the products, their side effects slightly different but they share the risk of increased blood levels of potassium (potentially very serious). Other effects of hormonal disorders resulting in such a volume increase of the breast, impotence or menstrual disorders, digestive problems or headaches.
- Inhibitors of angiotensin converting enzyme or IEC
As their name implies, they block an enzyme converting enzyme. This naturally involved in the formation of vasoconstrictor compounds (ie, that constrict the blood vessels) as angiotensin II. Blocking this enzyme limits the production of these compounds and allows a reduction in blood pressure. They may result from other dry cough, headache, taste disorders or digestive. They are cons-indicated in pregnancy or lactation but also in case of allergies, pregnancy and lactation, stenosis of the renal artery.
- Inhibitors of angiotensin II
Unlike ACE inhibitors, these drugs do not prevent the formation of angiotensin II, but its action. Now angiotensin II is essentially the most known hypertensive. This class of antihypertensives is the last appeared. They can cause headaches and dizziness.
The associations of antihypertensive
They are often used because they reduce the dosage of each drug used and therefore their respective side effects. In some cases even the side effects are opposed, for example, in associations of both classes of diuretics for which the reduction and increase in blood potassium vanish more or less. Given the number of anti-hypertensives, the possibilities are endless Association and have more or less side effects, indications and cons of each component. |
