Irritants. Medical encyclopedia - irritants Irritants include

Irritants are drugs that, upon contact with sensitive nerve endings, cause their depolarization and excitation, providing a local irritating effect, accompanied by reflex reactions in the form of improved blood supply and tissue trophism, and pain relief.

Neurohumoral action. It is caused by the resorptive effect of biologically active substances that are formed in the area of ​​skin irritation, as well as by increased afferent impulses from neurons of the reticular pharmacy. In this case, a change in the exchange of brain mediators occurs:

Antinociceptive factors are released: β-endorphin, enkephalin.

The release of nociceptive mediators is reduced: substance P, somatostatin, cholecystokinin.

The secretion of releasing hormones, ACTH, TSH increases, which ultimately increases the activity of the hypothalamic-pituitary-thyroid and hypothalamic-pituitary-adrenal systems, which have an anti-inflammatory effect.

M enthol (Menthol) It is a terpene alcohol and has a very strong mint smell and cooling taste. The local effect is associated with an effect only on cold receptors, therefore, immediately after application it causes a feeling of coldness, which turns into mild terminal anesthesia. At the same time, vasoconstriction of the skin and mucous membranes develops at the site of menthol application and swelling decreases. Thus, the local effect of menthol has a number of significant differences from the action of other irritants.

The reflex action is associated with the development of cutaneous-visceral reflexes, the reflex arc of which does not affect the brain, but closes at the level of the spinal cord. It manifests itself in the form of expansion of spasmodic vessels of internal organs and skeletal muscles, as well as contraction of the vessels of the meninges. Previously, they tried to use menthol to relieve attacks of angina (as part of Validol tablets for sublingual use). However, its effect was comparable to the placebo effect. This is explained by the fact that the basis of attacks of classical angina is not a functional spasm, but an organic narrowing of the lumen of the vessel by atherosclerotic plaques.

Additional effects:

In small doses when administered orally, it has a carminative (carminative) effect, which is characterized by moderate stimulation of gastrointestinal motility and relaxation of the sphincters, resulting in improved gas discharge.

When taken in large doses, it can have a resorptive effect, which is manifested by a decrease in blood pressure and depression of the central nervous system.

At the site of application it has a non-selective antiseptic effect due to the dissolution of bacterial cell membranes in lipids and disruption of their normal functioning.

Indications for use and dosage regimens:

For inflammatory diseases of the upper respiratory tract (rhinitis, pharyngitis, laryngitis, tracheitis) - in the form of inhalations, lozenges and nasal instillations 4-6 times a day.

For neuralgia, myalgia and arthralgia - in the form of rubbing in a 2% alcohol solution or 10% oil suspension 3-4 times a day.

For migraine - rubbing the reflexogenic zones of the trigeminal nerve (temple, forehead) with a pencil during an attack.

To relieve nausea, suck on lozenges or tablets.

To eliminate the undesirable effect of nitroglycerin (facial hyperemia and headache caused by dilatation of the vessels of the meninges) - in the form of a tablet under the tongue simultaneously with taking nitroglycerin.

NE: Oral administration in large doses causes abdominal pain, nausea, vomiting, and dizziness. In children 1 year of age, contact with the mucous membranes of the nasopharynx can cause reflex depression and respiratory arrest. Sometimes causes allergic reactions in the form of contact dermatitis.

FV: powder, menthol oil 1 and 2% in 10 ml bottles, menthol alcohol solution 1 and 2%, menthol pencil ( StilusMentholi). Combined medications: Gevkamen ointment ( « Geucamenum» ), tablets "Pectussin" ( « Pectussinum» ), validol (25-30% solution of menthol in methyl ester of isovaleric acid) tablets of 60 mg, etc.

Purified turpentine oil (OleumTerebinthinaerectificatum) It is an essential oil (the main component is -pinene), obtained by distilling resin from Scots pine (Pinus silvestris L.). It has the appearance of a transparent, colorless, mobile liquid with a characteristic odor and pungent taste.

It has a local and reflex irritating effect and a neurohumoral effect. They are used mainly externally as part of ointments and liniments for rubbing against neuralgia, myositis, and neuritis. Sometimes prescribed for inhalation (10-15 drops per 200 ml of hot water) for purulent bronchitis and bronchiectasis.

NE: Nausea, vomiting, albumin and hematuria when taken orally. When applied topically in high doses, it causes erythema and a vesicular eczema-like rash.

FV: bottles of 50.0; turpentine ointment (Unguentum Terebimthinae) jars of 50.0; complex turpentine liniment (Linimentum Olei Terebinthinae compositum) bottles of 80 ml.

Ammonia solution (SolutioAmmoniicaustici) It is an official solution of 9.5-10.5% ammonia in water with a pungent characteristic odor and a highly alkaline reaction.

MD: Has a reflex irritant effect when inhaling vapors. Ammonia activates the receptors of the sensory endings of the trigeminal nerve in the nasopharynx and enhances the flow of impulses from them to the nuclei of the respiratory center and the activating part of the reticular formation of the brain stem. This causes faster and deeper breathing and increased vascular tone.

Application:

As an emergency treatment for syncope to return the patient to consciousness. To do this, a small piece of cotton wool or a gauze ball is moistened with an ammonia solution and brought to the nostrils for 0.5-1 s.

Orally as an emetic (5-10 drops per ½ glass of water) for alcohol and drug intoxication (only if the patient is conscious).

Previously, in surgical practice, it was widely used for washing hands according to the S.I. method. Spasokukotsky – I.G. Kochergin based on the nonspecific antimicrobial effect of ammonia associated with damage to the lipids of bacterial membranes. Used at the rate of 25 ml per 5 liters of warm boiled water (0.5% solution).

NE: When high concentrations of ammonia vapor are inhaled, reflexive cessation of breathing is possible. Locally – colliquation burns of mucous membranes and skin. Help for burns consists of washing the area of ​​contact with ammonia with water for 15 minutes or with a 0.5-1.0% solution of citric acid. It is prohibited to use oils and oil-based ointments when providing care within 24 hours after a burn.

FV: liquid in bottles of 10, 40 and 100 ml, ampoules of 1 ml. Combined preparations: ammonia liniment ( Linimentumammoniatum), ammonia-anise drops ( LiquorAmmoniianisatus) liquid in 25 ml bottles.

1Medicines from the group of expectorants, bitters, choleretic and laxatives will be discussed in the relevant sections devoted to the pharmacology of drugs that affect the functions of the executive organs.

2 The dependence of the amount of ionized and non-ionized fraction of the main drug substance in tissues at different pH values ​​is determined by the Henderson-Hasselbach relationship:
. By substituting alternately the minimum and maximum values ​​of pH and pK BH + into the equation, it is easy to calculate the fraction of non-ionized drug.

3 Previously used as a local anesthetic, cocaine differs in its resorptive effect from other local anesthetics: it causes stimulation of the central nervous system, an increase in the force of heart contractions, tachycardia and an increase in blood pressure due to vasoconstriction. This uniqueness is due to the combination of local anesthetic and sympathomimetic effects in cocaine.

4The antiarrhythmic properties of lidocaine are discussed in more detail in the corresponding section

5Previously, the pharmaceutical industry produced 250 mg tablets intended for oral treatment of arrhythmias. However, taking pills did not have any effect on the course of arrhythmia, since their bioavailability was less than 1% due to intensive first-pass metabolism.

6Currently Helicobacter pylori plays one of the leading roles in the development of gastric and duodenal ulcers.

7 When treating diarrhea of ​​infectious origin (preservation of loose stools for more than 48 hours or the presence of fever), it is also necessary to prescribe antibacterial agents and replenish fluid losses.

Subject: " Irritants"
Plan:

1) General characteristics of irritants.

2) Mechanism of action.

3) The mechanism of reflexive, “distracting” action.

4) Classification.

5) Application.
Irritants include drugs that excite the endings of afferent nerves, causing reflex and local effects: redness of the skin, improvement of blood supply, tissue trophism, reduction of pain and inflammation. Apply externally in the form of rubbing, ointments, balms, nasal drops.

Mechanism of action: irritate, excite the endings of afferent nerves (receptors) embedded in the skin, which selectively respond to certain types of irritations (pain, temperature). As a result, there is a local (local) release of autocoids, biologically active substances (kinins, histamine, prostaglandins), which have a local vasodilator, hyperemic (cause redness) effect with improved tissue nutrition and improved blood circulation. In this case, deep blood vessels (for example, coronary vessels) reflexively dilate. As a result of the “distracting” effect of irritants, pain in areas of inflammation decreases or completely disappears.

Mechanism of reflexive, “distracting” action: p When there is inflammation, pain impulses continuously enter the corresponding segment of the spinal cord, from there they enter the higher parts of the central nervous system, where they create a focus of persistent excitation of the nerve centers, the so-called “pain dominant focus.” When an irritating agent is applied to the corresponding area of ​​the skin, a new stream of impulses of a different nature arises. A new dominant focus of excitation is created in the central nervous system, and the old one fades away, pain sensations weaken or disappear altogether. Therefore, irritants are applied to the area of ​​the skin that receives afferent innervation from the same segment of the spinal cord as the diseased organ.

Classification:

1.Irritants containing essential oils of plants:

A) Menthol preparations from peppermint leaves:

“Validol” tablets, “Pinosol” nasal drops (menthol and pine oil),

peppermint tincture, 10% menthol oil solution, Menovazin alcohol solution (menthol, novocaine, anesthesin).

Menthol preparations, when applied to the mucous membranes and skin, excite cold receptors, cause a feeling of cold, a reflex narrowing of superficial blood vessels and a weakening of pain sensitivity at the site of application. However, the tone of blood vessels and smooth muscles of deep-lying organs may expand. The mechanism of action of Validol tablets is based on this. It is taken sublingually; the menthol it contains irritates the cold receptors of the oral mucosa, which causes a reflex expansion of the coronary vessels and a decrease in pain in the heart. Used for pain in the heart from spasm of the coronary vessels during mild attacks of angina.

Mint tincture is taken orally, 15-20 drops per ¼ glass of water for spasms of the biliary tract. An oily 10% menthol solution is instilled into the nose for rhinitis to reduce inflammation and facilitate nasal breathing. Ointments containing 1-2% menthol and Menovazin are used for skin diseases accompanied by itching, for rubbing for neuralgia, muscle and joint pain, migraines (rubbed into the temples) as well as other irritants.

B) Combined drugs:

aerosols "Inhalipt"(streptocide, norsulfazole, eucalyptus oil, peppermint oil); "Kameton" ( camphor, menthol, eucalyptus oil), ointments "Efkamon", "Gevkamen" ( menthol, camphor, clove oil, eucalyptus), "Ben-gay"(menthol, methyl salicylate), "Bom-benge"(camphor, menthol, eucalyptus oil).

Capsaicin is isolated from the fruits of capsicum, which is part of combined ointments. "Espol", "Captrine", "Nicoflex", tinctures of capsicum, pepper plaster. Pepper patch is used for longer effects.

The glycoside sinigrin, which is part of mustard plasters, is isolated from mustard seeds. Mustard plasters are moistened only with warm water, because When it is hot, sinegrin is inactivated, when it is cold it is not activated, and when it is warm it breaks down to form the irritating substance allyl thiocyanate. When applied to the calf muscles, mustard plasters cause a reflex expansion of the coronary vessels and lower blood pressure; as a distracting agent, they are applied between the shoulder blades for chest pain with bronchitis, for sore throat in the back of the head and throat, for muscle pain in the lumbar region and ribs, for some gynecological diseases in the area below the navel.

Purified turpentine essential oil (turpentine) is obtained by distilling the resin of Scots pine and is used independently, as part of turpentine ointment and other ointments.

bee venom “Apizatron”, “Apifor”, “Ungative”;

snake venom “Viprasal”, “Vipraxin”, “Nayatox”, “Nayaksin”.

3.Synthetic irritants:

ammonia solution 10% (ammonia), used for fainting, apply 1-2 drops to a cotton swab and give the patient a sniff, while the receptors of the upper respiratory tract are irritated, which reflexively excites the central nervous system and consciousness returns.

For rubbing use formic alcohol, ointments "Kapsikam" "Finalgon"(nicotinic acid butoxyethyl ester). Finalgon is applied in a small amount, no more than a pea, distributed on the skin with a special applicator, and in case of severe pain, removed with a dry cloth.

Application: in the complex treatment of arthritis, myositis, neuritis, neuralgia, acute and chronic lung diseases, and for the treatment of bedsores, camphor alcohol is used to improve local blood circulation.

Side effects: with prolonged contact of irritating agents with the skin, a burn with subsequent inflammation is possible, therefore, if severe pain occurs, it is necessary to stop using the drug.
Test questions for consolidation:
1. How does the mechanism of action of irritating agents differ from enveloping, astringent, and adsorbent agents?

2. What combination menthol preparations are available?

3. What is the peculiarity of the action of menthol preparations?

4.What is the essence of the distracting effect of irritants?

5.What precautions should be taken when using irritants?
Recommended reading:
Mandatory:

1.V.M.Vinogradov, E.B. Katkova, E.A. Mukhin “Pharmacology with prescription”, textbook for pharmaceutical schools and colleges / edited by V.M. Vinogradov-4th edition - St. Petersburg: Special. Lit., 2006-864 pp.: ill.
Additional:

1. M.D. Gaevy, P.A. Galenko-Yaroshevsky, V.I. Petrov, L.M. Gaevaya “Pharmacology with prescription”: Textbook. – Rostov n/d: publishing center “MarT”, 2006 – 480 p.

2.M.D. Mashkovsky “Medicines” - 16th ed., revised.. corrected. And additional - M.: New Wave: Publisher Umerenkov, 2010. - 1216 p.

3. Directory VIDAL, Medicines in Russia: Directory. M.: AstraFarmService, 2008 - 1520 p.

4. Atlas of medicines. – M.: SIA International LTD. TF MIR: Eksmo Publishing House, 2008. – 992 p., ill.

5. N.I. Fedyukovich Reference book on medicinal products: in 2 hours. Part. P.. - Mn.: Interpressservice; Book House, 2008 – 544 p.

6. D.A. Kharkevich Pharmacology with general formulation: Textbook for medical schools and colleges. – M,: GEOTAR – MED, 2008, - 408 p., ill.
Electronic resources:

1.Electronic library for the discipline. Lecture on the topic “Irritants”.

These substances stimulate (excite) sensory receptors. Irritation of receptors in the skin and mucous membranes leads to impulses that, through the central nervous system, cause a response from organs or muscles. Consequently, the mechanism of action of irritants is reflex. In addition, they have a local and distracting effect.

The reflex action of irritants is easy to observe when using an ammonia solution (ammonia) for fainting. After inhaling its vapors, the receptors of the upper respiratory tract are irritated and reflex excitation of the central nervous system and respiratory center occurs, after which the impulse reaches the lungs and exhalation occurs, as a result of which breathing increases and consciousness is restored. A similar effect is exerted by menthol in the composition of validol, the action of which reflexively dilates the blood vessels of the heart, which is used in the treatment of angina pectoris.

The distracting and therapeutic effect of irritants is used for inflammatory diseases of the respiratory system, internal organs, muscles, joints, etc. The basis of the irritating effect is the effect of drugs on certain areas of the skin on the human body (Zakharyin-Ged zones), which have conjugate innervation with internal organs. For example, for inflammatory diseases of the respiratory system, rub the chest, shoulder blade area with irritating agents, or use mustard plasters.

The local effect of irritants manifests itself in the form of a burning sensation, warmth, tingling and redness. At the same time, blood vessels dilate, nutrition of diseased organs and tissues improves, blood flow, the number of leukocytes and phagocytes increases, which helps reduce the inflammatory process and activates the functional state of an organ or muscle.

Irritation of the receptors of the nasal mucosa with menthol, on the contrary, leads to a narrowing of blood vessels, thickening of the cell membranes, a decrease in swelling of the mucous membrane and the cessation of secretion during a runny nose, dilation of the nasal passages and easier breathing.

Irritants are used to treat inflammatory diseases of the respiratory system (bronchitis), muscles (myositis), nerve roots of the spinal cord (sciatica), joints (arthritis), runny nose (rhinitis), etc.

Irritants include mustard plasters, ammonia solution, menthol preparations, purified turpentine oil (turpentine), pepper plaster, various rubbings that contain alcohol, camphor, salicylic acid, snake or bee venom.

MUSTARD PLASTERS (Sinapismata) are sheets of paper covered with low-fat mustard. Before use, they are moistened with warm 36-40 °C water and applied in this form to certain areas of the skin for 5-15 minutes. Their therapeutic effect is due to a reflex reaction resulting from irritation of the nerve endings of the skin with essential mustard oil.

AMMONIA SOLUTION (SolutioAmmonii caustici) is a transparent, volatile liquid with a pungent characteristic odor, containing about 10% ammonia. It is used for reflex stimulation of breathing and restoration of consciousness in case of fainting, poisoning, injuries, for which a cotton swab moistened with an ammonia solution is carefully brought to the nose. Sudden inhalation of large doses of ammonia vapor can cause a decrease in heart rate and respiratory arrest (!).

Sometimes an ammonia solution as an emetic, 5-20 drops in 0.5 glasses of water, is prescribed for poisoning, for example, with alcohol.

In surgical practice, an ammonia solution (25 ml per 5 liters of warm water) was previously used to treat the surgeon’s hands according to the method of S.I. Spasokukotsky and I.G. Kochergina as a good detergent and antimicrobial agent.

Release forms: 30 ml bottles, 1 ml ampoules.

MENTHOL (Mentholum) - crystalline powder with a minty odor and cooling taste. When rubbed into the skin or applied to mucous membranes, it causes a feeling of cold, slight burning and tingling, and has a weak local analgesic, sedative and antimicrobial effect.

Menthol is used for inflammatory diseases of the upper respiratory tract (rhinitis, pharyngitis, tracheitis) in the form of 1 and 2% oil solutions, in the form of tablets, lozenges for resorption in the oral cavity, nasal drops, as well as for lubricating mucous membranes and inhalations.

For neuralgia, myositis, joint pain, 1 and 2% alcohol solutions are used as rubbing, and for migraines, rub the skin in the temple area with a menthol pencil.

Menthol is included in Validol tablets, is a component of Zelenin drops and the drug Corvalol, Boromenthol, Efkamon ointments, and the anesthetic liquid "Menovazin".

Release form: powder, 1 and 2% menthol oil solution, 1 and 2% alcohol solution, menthol pencil.

PURIFIED TERPENTINE OIL (Oleum Therebinthi-pae), or purified turpentine, is a clear, colorless liquid with a characteristic odor and pungent taste. It is used as an irritant and distracting agent in ointments, liniments, rubbing for myositis, radiculitis, rheumatism, colds, respiratory diseases, etc.

Release form: in 50 ml bottles and in the form of 10% ointment.

In addition to the listed drugs, the group of irritants includes tincture of pepper (hot), pepper plaster, drugs containing bee and snake venom, as well as emetics, laxatives and other drugs.

The skin and mucous membranes contain sensitive nerve endings (pain, temperature, chemical), irritation of which causes a flow of impulses into the central nervous system and a reflex response. - these are substances that stimulate sensitive nerve endings and cause local and reflex reactions that determine the pharmacological effect of the drug.

Pharmacological characteristics of irritants

ᐅ Mustard paper (mustard plasters) used for respiratory diseases, neuralgia, myalgia, angina pectoris. Mustard paper is used as follows: sheets of this paper must be moistened in warm water (35-40°C) and applied to the corresponding area of ​​the body.

The indicated water temperature is of fundamental importance, since the mechanism of the irritating effect of mustard is based on the enzymatic reaction of the breakdown of the sinigrin glycoside contained in mustard powder. Sinigrin, under the influence of the enzyme myrosin, which is activated in warm water, attaches a water molecule and breaks down to glucose, potassium hydrogen sulfate and allyl isothiocyanate, which is an irritant.

At higher water temperatures, the enzyme myrosin, being a protein, undergoes coagulation and loses its activity. As a result of coagulation of myrosin, hydrolysis of sinigrin does not occur and mustard paper does not have its irritating effect.

ᐅ Purified turpintine oil (turpentine) is a liquid mixture of terpenes and terpenoids obtained from oleoresin resin. Turpentine has significant lipophilicity and therefore penetrates the epidermis and has an irritating effect on the endings of sensory nerves. Preparations containing turpentine oil (capsicam, viprosal) are used topically for rubbing for neuralgia, myalgia, and joint pain.

ᐅ Menthol is the main biologically active substance of peppermint essential oil (Mentha piperita L.). Menthol has the ability to selectively excite cold receptors (minor anesthesia), reflexively change the tone of blood vessels, tissues and internal organs. Menthol is used for inflammatory diseases of the upper respiratory tract, angina pectoris, neuralgia, myalgia, arthralgia, etc. It is part of many combination drugs, in particular, it is the main component of a reflex vasodilator validol.

ᐅ Ammonia solution (ammonia). The active ingredient in ammonia is ammonia gas (NH 3), which easily evaporates from solution. When inhaling ammonia vapor, it excites the endings of the sensory nerves of the upper respiratory tract and reflexively stimulates the breathing center. In addition, ammonia easily penetrates the central nervous system (since it is highly lipophilic) and causes stimulation of the cortex and subcortical structures of the brain (especially the centers of the medulla oblongata). Due to this property, ammonia is used in the form of inhalations for fainting and intoxication. Also, when used internally, ammonia irritates the chemoreceptors in the stomach, which can cause vomiting. Finally, ammonia has antiseptic properties and is used to clean the surgeon's hands before surgery.

Drugs that excite the endings of sensory nerve fibers and cause reflex or local effects: improving blood supply and tissue trophism, reducing pain.

Irritants are used externally, often in the form of rubbing. They have a nonspecific stimulating effect on nerve endings (receptors) embedded in the skin, which selectively respond to certain types of irritations (pain, temperature, etc.).

The following are used as irritants:

1. Preparations containing essential oils from peppermint leaf (the active principle is menthol), eucalyptus leaf (eucalyptus oil is included in the preparations “Ingalipt”, “Eucamon”, “Pectusin”), capsicum fruits (contain capsaicin, which is included in in the composition of ointments “capsitrin”, nikoflex”), mustard seeds (mustard paper), as well as camphor alcohol, purified turpentine oil (turpentine), “Golden Star” balm (contains eucalyptus, clove, mint oils, cinnamon and other substances) .

2. Preparations containing bee venoms (apisatron, apifor) and snake venoms (vipraxin, viprosal).

3. Synthetic preparations: chloroform, 10% ammonia solution (ammonia), formic alcohol, finalgon ointment.

The pharmacological effects of irritants can be varied, for example, drugs containing menthol, when applied to the mucous membranes or skin, cause a feeling of cold associated with selective stimulation of cold receptors. In this case, a reflex narrowing of blood vessels occurs and a weakening of pain sensitivity at the site of application.

A popular irritant with a predominantly reflected effect are mustard plasters. Before use, mustard plasters must be moistened with warm water (not higher than 40° C). The glycoside sinigrin contained in mustard powder is broken down by the enzyme myrosin to form the irritating amyl isothiocyanate. If mustard plasters are placed in hot water, they lose their properties, since myrosin is inactivated at high temperatures. The scope of application of various irritating agents and procedures is very wide. They are used in the complex treatment of arthritis, myositis, neuritis and neuralgia, acute and chronic lung diseases, some gynecological diseases, regional circulatory disorders in the extremities, diseases of the musculoskeletal system, etc.

DRUGS.

Mustard plasters(Charta sinpis) are sheets of paper 8 × 12 cm, coated with a layer of low-fat mustard powder. Used for inflammatory diseases of internal organs, muscles, nerves, joints.

Ammonia solution(Solutio Ammonii caustici) transparent volatile liquid with a pungent characteristic odor. They are used for fainting, but it should be remembered that a large amount of ammonia vapor can cause a sharp decrease in heart rate and respiratory arrest.

F.v.: ampoules of 1 ml.

Purified turpentine oil(Oleum Terebinthinae rectificatum) essential oil obtained by distilling resin from Scots pine.

F.v.: bottles of 50 ml, turpentine ointment 50.0, turpentine liniment 80 ml.

Menthol(Mentholum) colorless crystals with a strong peppermint odor and cooling taste. Locally for neuralgia, myalgia, joint pain (2% alcohol solution, 10% oil solution); for migraines (menthol pencil, which is rubbed on the skin in the temple area); for inflammatory diseases of the upper respiratory tract - runny nose, pharyngitis, laryngitis (nose drops, lubricants, inhalations).