Anaesthetic substances in direct contact with the tissues paralyzing receptor education and blocking transmission of impulses along nerve fibers. To anesthetic tools include cocaine novocaine, dikain, benzocaine, xican, trimekain and Savkin.
Various receptors differ different sensitivity to anesthetic drugs and so they go off, not simultaneously, but in a certain sequence. First of all disappears pain sensitivity, then, smell, taste, temperature and last tactile. Nerve fibers also have different sensitivity to anesthetic agents. The conduction of impulses on sensitive fibers stopped ahead of or exposure to lower concentrations of anaesthetics than motor.
Action anaesthetics depends on the degree of blood supply to tissues. At reduction of blood supply to tissues efficiency anesthetic action anaesthetics strengthened; in addition, by reducing absorption anaesthetics increase the duration of their action and reduces the possibility of poisoning. In this regard, the solutions anaesthetics often add sossoudossoujiwath funds, often adrenaline. On the action anaesthetics impact and reaction of environment: in alkaline medium it increases in acid - weakened. This explains the fact that anaesthetics not render the expressed action when introducing them into inflamed tissue. It should be noted that xican, trimekain, Savkin slow to break down the tissue and therefore have a more prolonged action than other anesthetics (cocaine novocaine and others).
Anesthetics used for different types of local anesthesia. Anaesthetics, a well penetrating through the epithelial mucous membranes,- dikain, xican and cocaine - is used for surface anesthesia; novocaine, trimekain and xican - for infiltration and block anesthesia; Savkin, novocaine and xican-for spinal anaesthesia. Benzocaine is used only for surface anesthesia.
Among anaesthetics especially toxic Savkin, dikain, cocaine. In case of poisoning by these compounds there excitation of the Central nervous system and the subsequent development of paralysis. With the purpose of prevention of possible toxic effects of cocaine and dikaina recommended for 40-50 minutes until the anesthesia to give to the patient barbiturates (for example, barbanel 0.1 g). The use of analeptics (koratala, caffeine and other) when caused anesthetic means oppression centers of the medulla oblongata is usually ineffective. In severe poisoning, anesthetic means apply artificial respiration, oxygen (Carbogen), bloodletting with the subsequent introduction of an isotonic solution of sodium chloride. Separate anaesthetics - see the article by name drugs (e.g. Cocaine, Savkin and others).

Anaesthetics (Anaesthetica; GK. anaistliesia - insensitive) - medicinal substance that resolves anxiety of end devices sensitive nerves b blocking conduction of impulses through the nerve fibers. Action anaesthetics selectively, i.e. apparent in such concentrations that do not harm surrounding tissues, and is reversible. The first A. E. introduced in medical practice, it was cocaine (see), which causes all kinds of anesthesia, but because of the high toxicity currently applied only to the surface anesthesia (in ophthalmology, otolaryngology and urology). Cocaine causes vasoconstriction; therefore it is included in the drops and ointments used in the treatment of rhinitis, sinusitis, conjunctivitis. Disadvantages of cocaine: high toxicity, impact on intraocular pressure, the instability in solution at sterilization by boiling, low accessibility of source receipt; in re-use of cocaine may develop pain of addiction (cocainism).
Benzocaine (see) and other alkyl esters aminobenzoic acid found limited application, as their soluble salts possess a local irritating effect. Wide dissemination in clinical practice received novocaine (see) and other esters of para-aminobenzoic acid (Benkin, chlorpromazine, Manokhin, Amelkin, Bukin, dikain, cornelian, oktanain and others), with less irritating and large anesthetic effects. Novocaine apply to all kinds of anesthesia (table), in addition to the surface, and in the treatment of various diseases. Novocaine considerably less toxic than cocaine, and has a great breadth of therapeutic action. Disadvantages of novocaine: the short duration of action, failure to cause surface anesthesia, antisulfanilamidnoe effect, the instability in the solution, the ability to cause allergic reactions. The solution is the Foundation of novocaine in peach oil is used with long-term pain scars, fissures, after surgery hemorrhoids, etc.; its effect after a single injection under the skin or into a muscle lasts from 3 to 15 days. Dikain (see) - a strong anesthetic agent, activity and toxicity superior novocaine and cocaine. Due to the high toxicity dikain mainly used for the surface benzocaine in ophthalmology and otolaryngology.
Wofacai, oxiprolin (Pascain) and other esters paraaminosalicilovaya acid similar activity to the group of novocaine, but differ from them by the presence of anti-inflammatory and antiseptic properties. Wofacai more cocaine on the surface anesthesia and is successfully used in otolaryngology. Connection with the amide bond widespread Savkin (see), superior activity novocaine, cocaine and xican. As Savkin highly toxic and slowly eliminated from the body, it is used with great care, mainly for spinal anaesthesia. Folicain surpasses on the surface anesthesia cocaine, when wiring - novocaine, but more toxic it in 10 times (see table).
Recently attracted the attention connection with anilides communication. These include high-level, long-term and low-toxic anesthetics: xylocain (xican), trimekain (see), carbochain (mepivacain), jostakin. They squeezed from the practice novocaine (infiltrazionnaya, wiring, intraosseous anesthesia and for closure), dikain (at surface and epidural anesthesia), Savkin (in spinal anaesthesia) and other anesthetics, as have a number of advantages: call coming faster, deeper and more prolonged anesthesia than novocaine, have an analgesic effect in the postoperative period, do not cause allergic reactions, relatively low toxicity (less toxic than cocaine, dikain, Savkin), superior in therapeutic latitude commonly used anaesthetic, do not have antisulfanilamidnoe actions stand in the solution and when sterilization.

The mechanism of action of anaesthetics due to their adsorption on the surface of cells and the interaction with specific (chemically) structures of the receptor. Physico-chemical properties of A. S. - solubility, basicity, the dissociation constant, lepidopterist, polarity, surface activity and others, determining the ease of penetration A. S. through various biochemical environment and the possibility of contact with sensitive nerve significantly affect the anesthetic action. Penetrating into the nerve cell, anesthetic enter into chemical interaction with protein macromolecules nerve fibers are involved in the transmission of impulses. The effect of anaesthetics exacerbated and prolonged when the alkalinization of their solutions, adding salt To and Mg, serum, polyvinylpyrrolidone, and some other substances. Potenziruut effect A. S. analgesics morphine group, neurologiske substances, anticholinesterase agents and other Adrenaline, mezaton, ephedrine, naphazoline causes narrowing of the blood vessels, slow down the absorption of anaesthetics and thereby prolong action and reduce their toxicity. Anesthetic action reduced in the acidification of the solution A. E., the addition of glucose, urea, serotonin and in conditions of radiation.
A. S. are intended primarily for anesthesia during surgical operations. The activity and toxicity A. S. are manifested differently in various types of anesthesia: surface, infiltration, wire and other types of anesthesia. The application of A. S. particularly shown in the operations in open injuries, patients with traumatic shock, a weakened patients with malignant tumors, severe infectious diseases, spilled peritonitis, sepsis. Anesthetics applied also in case of neuritis, neuralgia, radiculitis. A. S. applied intravenously, intramuscularly and to blockade in the treatment of various diseases. A. S. sometimes combined with neurologicznej ganglioblokirute funds relaxers, steroid drugs. The application of A. S. is contraindicated in patients with unstable nervous system in young children, in patients with extensive purulent processes, with atypical operations on the internal organs, if you have large growths and adhesions.
Local reaction toxic character from A. S. manifests itself as the tissue edema, necrosis and dermatitis; it is more often expressed in the application neizotermicheskogo solutions A. S. Resorptive action A. S. mostly initially evident in the stimulation of the cerebral cortex, hypothalamus and centers of the medulla oblongata; then develops ganglioblokirtee, curariform and m-holinoliticescoe effect. In case of poisoning anesthetic means are observed: paleness, nausea, vomiting, motor excitation, breaking into clonicotonic convulsions; in more severe cases, the initiation of CNS changes its oppression breathing becomes superficial and wrong, blood pressure falls; the death results from respiratory arrest. Upon excitation of the Central nervous system prescribed drugs bromine, chloral hydrate, barbiturates, chlorpromazine and other drugs phenothiazine number; in case of collapse - caffeine, camphor, korazol subcutaneous epinephrine (0,1% 0,3 ml) intracardiac, glucose (30%) intravenously, do a blood transfusion. Some A. S. can cause allergic reactions (contact dermatitis, eczema, bouts of bronchospasm, urticaria, serum sickness).