Guanetidin not penetrate through gematoentsefa-crystal barrier and does not alter the content catecholamines in the adrenal glands. Pre-Preparata appointed interior. Both drugs differ in duration of action: after the cessation of the systematic antihypertensive effect may persist up to here weeks. As a dures the inhibitory effect of vagus nerve on the heart and decreases the stimulating effect of sympathetic innervation on heart and blood vessels. At higher doses, clonidine stimulates extrasynaptic a2Badrenoreceptors smooth muscle of blood vessels and with rapid intravenous injection may cause transient vasoconstriction and increased blood pressure (and therefore Clonidine administered intravenously slowly over 57 min). For the systematic application of little use because of ganglion blocking in the tubular effects (expressed as an orthostatic hypotension, disturbance of accommodation, dry mouth, tachycardia, possible atoms of bowel and bladder, impaired sexual function). Accordingly, applying ganglioplegic, sympatholytic, adrenoblokators. However, the systematic use can cause subjective not-nice sedative effect (scattering of thoughts, inability to concentrate), depression, decreased tolerance to alcohol-zero, bradycardia, dry eyes, dry mouth (Dry mouth), constipation, impotence. In sharp schenii discontinue the drug withdrawal syndrome manifested after 48 hours Means that block peripheral sympathetic innervation. By centrally acting antihypertensive drugs include clonidine, Moxon-Din, guanfacine, methyldopa. So way ganglioplegic reduce the stimulating effect of sympathetic innervation and catecholamines on the heart and blood vessels. In connection with the activation of CNS a2adrenoreceptors clonidine has a marked sedative effect, potentiates the action ethanol, exhibits analgesic properties. In the body of methyldopa becomes metilnoradrenalin and then metiladrenalin that amphetamine-liruyut dures center pressosensitive reflex. In sharp discontinuation of the drug develops a pronounced withdrawal syndrome: In vitro fertilization 18-25 h blood pressure rises, possible hypertensive crisis. Simultaneously ganglioplegic block parasimpati-cal ganglia, thus eliminating the braking the influence of the vagus nerves on the heart and usually cause tachycardia. Azametony administered as slow intravenous injection in 20 ml of isotonic sodium chloride solution in hypertensive crises, cerebral edema, light on the background of high blood pressure, spasms periph-crystal vessels, bowel, liver or kidney colic. Part of the hypotensive effect of clonidine is associated with activation dures a2adrenoreceptors on endings sympathetic adrenergic fibers - decreases the release of the NORAD-renalina. Activation of this center is to increase the frequency and force contractions of the heart (increased cardiac output) and increasing that of the cone of blood vessels - increased Tympanic Membrane pressure. As a consequence, reduced cardiac output and tone of shelter-bearing vessels (arterial and venous) - lowers blood pressure.
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