Annoying

Some synthetic substances and products of plant origin are referred to irritants. Of the synthetic substances, ammonia , formic acid , ethyl alcohol , dichloroethyl sulfide (mustard), trichlorotriethylamine , methyl salicylate , nicotinic acid derivatives (for example, nicotinic acid b- butoxyethyl ether , ethyl nicotinate ) and others possess these irritating properties . These substances are used as irritants various dosage forms intended for external use. For example, ammonia is used in the form of a solution of ammonia ( Solutio Ammonii caustici ) and ammonia liniment ( Linimentum ammoniatum ; synonym for “volatile ointment”); formic acid - in the form of formic alcohol ( Spiritus Acidi formici ), which is a mixture of 1 part of formic acid and 19 parts of 70% ethyl alcohol. Dichlorodiethyl sulfide is a part of Psoriazine ointment, trichlorotriethylamine is a part of Antipsoriaticum ointment, nicotinic acid b-butoxyethyl ester along with nonilinic acid vanillamide is a part of Unguentum Finalgon ointment, and ethyl ethylene glycosylate lavender oil - in the composition of Nicoflex cream (Nicoflex). Methyl salicylate is used per se or in a mixture with other irritating agents in a number of dosage forms, for example, Bom Beng ointment ( Unguentum Boum - Be nge), complex methyl salicylate linimentum ( Linimentum Methylii salicylatis compositum ), Sanitas linimentum ( Linimentum Sanitas " ), Salinimenta ( Salinimentum ).

Plant Irritants

Of the products of plant origin, many essential oils, some alkaloids, glycosides , saponins, and others have irritating properties. The essential oils used as irritants include peppermint oil and the main active ingredient of this oil is menthol, eucalyptus oil (Oleum Eucalypti), mustard essential oil oil, purified turpentine oil (synonymous with purified turpentine), camphor, etc.

Essential oils are used as irritants both in pure form and as part of various dosage forms and combination preparations containing essential oils and other plant and synthetic irritating substances. Such preparations include, for example, Efkamon ointment (Unguentum Efcamonum), which contains camphor, clove oil, essential mustard oil, eucalyptus oil, menthol, methyl salicylate, capsicum tincture, thymol, chloral hydrate, cinnamon alcohol, spermaceti and vaseline ; Aerosolum Camphomenum aerosol containing menthol, eucalyptus, camphor and castor oils, furatsilina solution, olive oil. The irritating effect of mustard plasters is due to the presence of essential mustard oil in them.

Of the preparations containing alkaloids, tincture and extract of capsicum, the active substance of which is capsaicin alkaloid, are used as irritants. In addition, tincture of capsicum is part of frostbite ointment (Unguentum contra congelationem), capsitrin (Capsitrinum), pepper-ammonia liniment (Linimentum Capsici ammoniatum), pepper-camphor liniment (Linimentum Carsici camphralum), and the extract is in the composition of capsicum pepper patch (Emplastrum Capsici). Of the plant products, moderately pronounced local irritating properties are possessed by birch tar and preparations in which it is included (for example, Vishnevsky balsamic liniment, Wilkinson ointment).

In addition to these irritating substances, there are drugs that belong to other groups of drugs that have irritating properties and cause certain pharmacological effects in a reflex way due to stimulation of mucous membrane receptors. For example, drugs that cause reflex enhancement of the secretion of bronchial glands belong to expectorants of a reflex type of action; laxative agents - for laxatives; drugs that simulate bile secretion - to choleretic drugs; appetite stimulants - to bitterness. The group of irritating substances also does not include preparations in which the local irritant effect is not the main but the side one.

The mechanisms of action of irritants are not well understood. It is known that with topical application of irritating agents they cause local tissue irritation, against the background of which pharmacological effects of a reflex and trophic nature can develop. In addition, irritants can weaken pain in the area of ​​affected tissues and organs due to the so-called distracting effect.

An example of the reflex action of irritants is the stimulating effect of an ammonia solution on respiration. When inhaled ammonia vapors, reflex excitation of the respiratory center occurs due to irritation of the upper respiratory tract receptors. In addition, ammonia vapors can probably influence the activity of the reticular formation of the brain stem, as afferent trigeminal systems are involved in maintaining its tone, the sensitive endings of which are partially localized in the upper respiratory tract. This explains the effectiveness of inhalation of the vapor of an ammonia solution in respiratory depression and fainting conditions. The reflex expansion of the coronary vessels of the heart (due to irritation of the receptors of the mucous membrane of the oral cavity) also determines the effectiveness of menthol preparations, such as validol, for attacks of angina pectoris.

The positive trophic effect of irritating agents on the internal organs is apparently carried out in various ways, primarily due to skin-visceral reflexes, the central links of which are located in the spinal cord. The afferent link of such reflexes is the skin afferent nerves, and the efferent link is the sympathetic nerves originating from the corresponding segments of the spinal cord. It is possible that some skin-visceral reflexes may also have the character of axon reflexes. In the mechanism of trophic effects of irritants, a certain role is probably played by the release of biologically active substances (for example, histamine ), which occurs with skin irritation. The trophic effect explains the therapeutic effect of irritants, mainly in diseases of internal organs (for example, mustard in lung diseases).

The distracting effect of irritating agents is manifested by the weakening of pain in the area of ​​affected organs and tissues. This effect is due to the fact that in the central nervous system there is an interaction of afferent impulse from organs affected by the pathological process and from the skin (from the area affected by irritating agents), as a result of which the perception of pain weakens. In physiological experiments, the possibility of this kind of interaction of nerve impulses entering the central nervous system via somatic and visceral afferent systems has been proven in relation to nerve centers located both in the spinal cord and in the brain. Based on this hypothesis, in order to obtain a distracting effect in diseases of internal organs, irritating agents should be applied to skin areas corresponding to Zakharyin - Geda zones. It is also possible that the weakening of pain under the influence of irritating agents occurs due to the activation of antinociceptive systems of the central nervous system (systems that regulate pain perception) and increased production of the so-called endogenous opioid peptides, that is, due to mechanisms similar to the mechanisms of the analgesic effect of some types of reflexology, for example acupuncture.

• Locally irritating

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