ANTIDOTES OF OB (the Greek antidoton given against antidote) — the pharmaceuticals warning or eliminating toxic action of OB. Modern OB can cause mass damages with violently proceeding intoxication therefore use of antidotes has crucial importance in system of the help to struck. Depending on conditions they can be applied with preventive or lay down. purposes.
On a way of action antidotes of OB can be divided into two groups: the antidotes of local action neutralizing OB before their absorption in blood and receipts in the bodies and fabrics, and the antidotes of resorptive action neutralizing OB in blood and bodies or operating on function of bodies by opposite relevant OB.
Efficiency of antidotes of local action is defined physical. - chemical (adsorption) or chemical (neutralization, oxidation, etc.) processes. Solutions of alkalis, chlorine-containing connections (chloroamine, hexachlormelamine), the special decontaminating solutions applied to processing of open body parts and the active coal used for binding of OB which got into a stomach belong to antidotes of OB of local action.
Efficiency of antidotes of resorptive action is caused by various processes.
1. Chemical interaction of antidotes and OB. Use of sodium thiosulphate at poisoning is based on it hydrocianic to - that.
2. The competitive relations between antidotes and active groups of proteins with OB therefore active groups of proteins are exempted from OB. Use of Unithiolum at poisoning with myshyaksoderzhashchy OB is based on this principle and reaktivator of cholinesterase at poisoning with organophosphorous OB (FOV).
3. Ability of antidotes to show the action opposite to action of OB in the physiological relation.
Use of atropine and other cholinolytic drugs at poisonings with antikholinesterazny and organophosphorous OB is based on this property.
According to specificity of action antidotes classify by groups or in relation to certain types of OB: antidotes of organophosphorous OB, hydrocianic to - you, myshyaksoderzhashchy OB, carbon monoxide, etc.
Cholinolytic drugs and reaktivator of cholinesterase belong to antidotes of FOV. FOV, having got to an organism, block cholinesterase and break mediator function of acetylcholine that leads to excitement and overexcitation of cholinergic systems and emergence of a typical picture of poisoning. In these cases use of the substances blocking muskarino-and nicotinosensitive holinoretseptor is proved. Great practical value as an antidote of FOV has atropine. Except it, as antidotes of FOV it is recommended to apply also other cholinolytics: taren, tsiklozit, amizyl, amidine, aprophene. Reaktivatorami of cholinesterase are drugs of group of oximes. It is established that under the influence of oximes activity of cholinesterase is recovered and atsetilkholinovy exchange is normalized. At the same time the great value gains their ability to eliminate the neuromuscular block of respiratory muscles. Other properties of oximes (neutralization of FOV, cholinolytic action, dephosphorylation of holinoretseptor) matter also in antidotal effect of drugs. Treat reaktivator of cholinesterase 2-PHAM-CHLORIDE, dipiroksy (TMB-4), toksogonin (LÜH-6), Isonitrosinum. The fullest antidotal effect is reached at use of cholinolytics in combination with reaktivator of cholinesterase.
Antidotes of FOV are the main means of the first medical aid struck, especially effective in an initial stage of intoxication. At further treatment along with antidotes use means of symptomatic therapy.
Methemoglobin formers, sulfur-containing connections and substances which part carbohydrates are belong to antidotes hydrocianic to - you. Toxic action hydrocianic to - you
are the cornerstone of it ability to interact easily with an oxide form of iron of cytochrome a3 (cytochrome oxydases) that leads to blockade of tissue respiration and development of a hypoxia. Antidotal action of methemoglobin formers is based on affinity hydrocianic to - you to humic pigments, ferric, including and to a methemoglobin. Hydrocianic to - that contacts a methemoglobin, forming tsianmetgemoglobin that in turn conducts to a delay in blood hydrocianic to - you and prevents blockade of cytochrome oxydase. At inhalation introduction of antidotes as methemoglobin formers amyle nitrite is recommended, at intravenous administration — solution of sodium nitrite. At effect of nitrites there is a bystry formation of a tsianmetgemoglobin, however further in process of dissociation of a tsianmetgemoglobin hydrocianic to - that is released again. At the same time it is necessary to use antidotes with other mechanism of action. Sulfur-containing antidotes, napr, sodium thiosulphate are most effective in this respect.
Antidotal action of sulfur-containing connections is based on their ability to neutralize hydrocianic to - that by its transformation into rhodanate connections. Neutralization happens to participation of enzyme of a rodaneza within several hours.
As sulfur-containing drugs are slowly operating antidotes, they are applied in a complex with other antidotes.
As an antidote methylene blue is also applied. Being hydrogen acceptor, methylene blue partially recovers function of dehydrogenases, i.e. activates process of oxidation. It is supposed that antidotal action is connected by hl. obr. with this property of drug.
Antidotal effect of carbohydrates (aldehydes and ketones) is based on formation of non-toxic chemical connections — cyan alcohols. The greatest distribution as a similar antidote was gained 25% by solution of glucose. The neutralizing effect of glucose comes rather slowly therefore it should be applied to treatment in a combination with other antidotes. Glucose also is a part of an antidote of a hromosmon (1% solution methylene blue in 25% solution of glucose).
Dithiol connections — Unithiolum, the BALL, Dicaptolum, dimekaptol, dithioglycerin belong to antidotes of myshyaksoderzhashchy OB (lewisite). These antidotes, except OB, neutralize in an organism of compound of mercury, chrome and other heavy metals (except lead). Toxic action of myshyaksoderzhashchy connections is caused by blockade of thiol groups of proteinaceous components of some fermental systems. The mechanism of action of antidotes is explained by their ability to compete with molecules of protein for connection with myshyaksoderzhashchy OB and heavy metals owing to structural proximity with SH groups of some enzymes. There is a chemical neutralization test of OB and formation of the soluble compounds which are quickly deleted from an organism. Use of Unithiolum in an initial stage of intoxication, however is the most effective and in 4 — 5 hours after poisoning the positive take is achieved.
A specific antidote of carbon monoxide is oxygen. Under the influence of oxygen dissociation of the carboxyhaemoglobin formed as a result of compound of carbon monoxide with bivalent iron of hemoglobin accelerates, removal of carbon monoxide from an organism accelerates. With increase in partial pressure of oxygen its efficiency increases.
The characteristic of the main antidotes and pharmaceuticals applied to prevention and treatment of poisonings with organophosphorous connections, cyanides, carbon monoxide and other poisons — see the table.
See also Antidotes .
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Yu. M. Polumiskov.