Carry the substances lowering system the arterial blood pressure and applied mainly to treatment and prevention of various forms of arterial hypertension, stopping of hypertensive crises and at other morbid conditions which are followed by spasms of peripheral blood vessels to hypotensive (antihypertensive) means.
The mechanism of action of various groups of antihypertensives is defined by their influence on different links of regulation of a vascular tone.
Main groups of antihypertensives:
- Kneyrotropnye the means reducing the stimulating influence on blood vessels of sympathetic (vasoconstrictive) impulses;
- K the myotropic means influencing directly unstriated muscles of vessels;
- Ksredstva, influencing humoral regulation of a vascular tone.
The substances influencing different levels of nervous control of a vascular tone are among neurotropic antihypertensives including:
- the means influencing the vasomotor (vasomotorial) centers of a brain (clonidine, Methyldopa, guanfatsin);
- the means blocking carrying out nervous excitement at the level of vegetative gangliyev (petrolhexonium, Pentaminum and other ganglioblokiruyushchy drugs);
- the sympatholytics blocking presynaptic nerves of adrenergic neurons (Octadinum, reserpine);
- means, the oppressing Ab A, a, an - and A b A + an - adrenoceptors (phentolamine, Tropaphenum, Prazozinum, anaprilin, atenolol, labetalol both other A an - and Ab - adrenoblockers and also "hybrid" Ab + A an - adrenoblockers).
A number of spasmolytic drugs, including papaverine, Nospanum, etc. carry to number of myotropic antihypertensives. However they have moderate antihypertensive effect and are used usually in combination with other means.
A specific place among myotropic means is held by peripheral vazodilatator (see).
In recent years antagonists of calcium channels (see) from which nifedipine and some of its analogs have the most significant antihypertensive effect received use as antihypertensives (nitrendipin, etc.).
In the mid-eighties the new group of the antihypertensives which are agonists (openers) of membrane potassium channels drew attention.
Drugs of this group cause an exit of potassium ions from cells of unstriated muscles of vessels (and other smooth muscle bodies), increase membrane potential and lead to hyperpolarization of a membrane, reduce cellular excitability.
Belong to this group of connections to kromakaly (Cromacalim), pinatsidit (Pinacidil), etc., offered for practical application as antihypertensive drugs. Also their efficiency in bronchial asthma, spasms of peripheral vessels, a syndrome of hyperexcitability of a bladder is studied.
Has agonistic impact on potassium channels also minoksidit (see).
New group of antihypertensive drugs are also blockers angiotensin - the converting enzyme (see Captopril).
As antihypertensive drugs groups of prostaglandins began to use drugs (see).
Also antagonists of Aldosteronum treat antihypertensive drugs which effect is connected with influence on humoral links of regulation of blood circulation (see Spironolactonum).
The important place in therapy of a hypertension belongs to diuretics (saluretics) which antihypertensive effect is caused by reduction of volume of the circulating blood plasma and also weakening of reaction of a vascular wall to vasoconstrictive sympathetic impulses.
The abundance of antihypertensive drugs allows to individualize therapy of various forms of arterial hypertension, but demands accounting of features of the mechanism of effect of drugs of different groups, the thorough choice of optimum means, accounting of a possibility of their side effects, etc.