Directory → Intermedianta → Gistaminergicakie funds → Gistaminolitiki → H_1-antigistaminne funds
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The groupThe first drugs that inhibit N_1-gistaminove receptors have been introduced in clinical practice in the late 1940s. They are called antigistaminnah because effectively inhibit the reaction of organs and tissues histamine. Gistaminovykh blockers N_1-retseptorov weaken caused gistaminom hypotension and cramps smooth muscles (bronchi, intestine and uterus), reduces the permeability of capillaries, hinder the development gistaminovogo pain, reduce hyperemia and skin and thus prevents the development, and facilitate the allergic reactions. The term "antihistamines" fully reflects the range of pharmacological properties of these drugs because there are a number of other effects. This is partly due to structural similarity gistamina and other physiologically active substances, such as adrenaline, serotonin, acetylcholine, dofamin. The blockers gistaminovykh H_1-retseptorov can to a greater or lesser degree, to the properties or holinolitikov альфа-адреноблокатор��в (holinolitiki, in turn, may have antigistaminna activity). Some antihistamines funds (difengidramin, promethazine, hloropiramin, etc.) have a dampening effect on the central nervous system, increasing the general and local anaesthetics narcotic analgesics. They are used to treat insomnia, parkinsonizma as a protivokashlevykh and antiemetics. Related pharmacological effects can be avoided. For example, the sedate, with electricity, golovokrugeniem violation coordinate movements and low concentration, outpatient limits the use of certain drugs antigistaminnah (difengidramin, hloropiramin and other members of the generation I), particularly in patients with work calls for a rapid and coordinated mental and physical reactions. The existence of the majority of these funds holinoliticski action is dry mucous membranes predisposes to the deterioration of vision and urination, gastrointestinal dysfunction.
I medicines generation reversible competitive antagonists N_1-gistaminovh receptors. They are fast and short (appointed to 4 times a day). Their long-term use often leads to the loss of therapeutic efficacy.
Recently established blockers gistaminovykh H_1-retseptorov (antihistamines preparations II and III generation), those highly selective actions on N_1-retseptora (hifenadin, terfenadin, astemizol, etc.). These medicines would not significantly affect the other mediator system (holinergicakie, etc.) to pass through GEB (do not affect the central nervous system), and do not lose momentum in its long-term use. Many preparations II generation nekonkurentno contact N_1-retseptorami, and the resulting ligand-retseptornyi set a relatively slow dissociation, hence longer therapeutic actions (nominated once a day). Biotransformation most antagonists gistaminovykh N_1-retseptorov occurs in the liver with the formation of active metabolites. Several N_1-gistaminovh blocking receptors is the active metabolites known antigistaminnah preparations (cetirizin active metabolite gidroxizina, feksofenadin - terfenadina).